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Catalan number

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4369: 1761: 9944: 3681: 1867: 4536: 8845: 1877: 1935: 29: 9930: 1768: 10827: 2203: 4364:{\displaystyle {\begin{aligned}1-{\sqrt {1-4x}}&=-\sum _{n=1}^{\infty }{\binom {1/2}{n}}(-4x)^{n}=-\sum _{n=1}^{\infty }{\frac {(-1)^{n-1}(2n-3)!!}{2^{n}n!}}(-4x)^{n}\\&=-\sum _{n=0}^{\infty }{\frac {(-1)^{n}(2n-1)!!}{2^{n+1}(n+1)!}}(-4x)^{n+1}=\sum _{n=0}^{\infty }{\frac {2^{n+1}(2n-1)!!}{(n+1)!}}x^{n+1}\\&=\sum _{n=0}^{\infty }{\frac {2(2n)!}{(n+1)!n!}}x^{n+1}=\sum _{n=0}^{\infty }{\frac {2}{n+1}}{\binom {2n}{n}}x^{n+1}\,.\end{aligned}}} 12757: 1550: 9361: 9925:{\displaystyle \sum _{i_{1}+\cdots +i_{m}=n \atop i_{1},\ldots ,i_{m}\geq 0}C_{i_{1}}\cdots C_{i_{m}}={\begin{cases}{\dfrac {m(n+1)(n+2)\cdots (n+m/2-1)}{2(n+m/2+2)(n+m/2+3)\cdots (n+m)}}C_{n+m/2},&m{\text{ even,}}\\{\dfrac {m(n+1)(n+2)\cdots (n+(m-1)/2)}{(n+(m+3)/2)(n+(m+3)/2+1)\cdots (n+m)}}C_{n+(m-1)/2},&m{\text{ odd.}}\end{cases}}} 5342:. Each of the 20 possible monotonic paths appears somewhere in the table. The first column shows all paths of exceedance three, which lie entirely above the diagonal. The columns to the right show the result of successive applications of the algorithm, with the exceedance decreasing one unit at a time. There are five rows, that is  1851:
square cells, which do not pass above the diagonal. A monotonic path is one which starts in the lower left corner, finishes in the upper right corner, and consists entirely of edges pointing rightwards or upwards. Counting such paths is equivalent to counting Dyck words: X stands for "move right" and
5127:
for any path that we feed it, because the first vertical step starting on the diagonal (at the point marked with a black dot) is the only vertical edge that changes from being above the diagonal to being below it when we apply the algorithm - all the other vertical edges stay on the same side of the
8831: 1372:
This has a simple probabilistic interpretation. Consider a random walk on the integer line, starting at 0. Let -1 be a "trap" state, such that if the walker arrives at -1, it will remain there. The walker can arrive at the trap state at times 1, 3, 5, 7..., and the number of ways the walker can
1296: 4645:
The part of the path after the higher diagonal is then flipped about that diagonal, as illustrated with the red dotted line. This swaps all the right steps to up steps and vice versa. In the section of the path that is not reflected, there is one more up step than right steps, so therefore the
8470: 281: 8299: 8896:, which was completed by his student Chen Jixin in 1774 but published sixty years later. Peter J. Larcombe (1999) sketched some of the features of the work of Mingantu, including the stimulus of Pierre Jartoux, who brought three infinite series to China early in the 1700s. 7027: 4520: 3221: 6323: 943: 815: 8702: 5104:, and we place the last lattice point of the red portion in the top-right corner, and the first lattice point of the green portion in the bottom-left corner, and place X accordingly, to make a new path, shown in the second diagram. 5005: 2948: 8710: 1119: 8349: 103: 4853: 8610: 8178: 6790: 565: 1021: 8060: 5331: 1504: 6031: 1367: 5781: 7297: 678: 5048: 4374: 6801: 4706:
grid meets the higher diagonal, and because the reflection process is reversible, the reflection is therefore a bijection between bad paths in the original grid and monotonic paths in the new grid.
8545: 7375: 5108: 6596: 5132: 3358: 426: 5906: 3071: 3686: 3596: 3528: 9137: 7198: 7116: 6441: 7899: 5399: 3667: 5251: 5697: 3104: 6206: 826: 699: 7726: 7690: 7654: 7618: 7582: 4636: 3427: 8967: 8932: 8618: 6171: 9326:. The classical recurrence relation generalizes: the Catalan number of a Coxeter diagram is equal to the sum of the Catalan numbers of all its maximal proper sub-diagrams. 8999: 5586:
sides and a (different) triangulation, again mark one of its sides as the base. Mark one of the sides other than the base side (and not an inner triangle edge). There are
5475: 6504: 456: 6067: 7464: 4646:
remaining section of the bad path has one more right step than up steps. When this portion of the path is reflected, it will have one more up step than right steps.
9324: 9297: 9236: 9038: 7847: 6198: 6106: 5426: 2740: 1427: 7974: 6470: 2984: 2413: 2341: 2303: 2265: 1400: 9204: 9178: 8086: 7925: 7795: 7546: 7520: 7490: 5501: 2850: 6622: 4858:
and the number of Catalan paths (i.e. good paths) is obtained by removing the number of bad paths from the total number of monotonic paths of the original grid,
1063: 9256: 8106: 7945: 7815: 7769: 7749: 7438: 7418: 6662: 6642: 6382: 6362: 2824: 2804: 2784: 2764: 5018:
Y's and interchange all X's and Y's after the first Y that violates the Dyck condition. After this Y, note that there is exactly one more Y than there are Xs.
1526:
contains a set of exercises which describe 66 different interpretations of the Catalan numbers. Following are some examples, with illustrations of the cases
10859: 8826:{\displaystyle \det {\begin{bmatrix}2&5&14&42\\5&14&42&132\\14&42&132&429\\42&132&429&1430\end{bmatrix}}=5} 4864: 2855: 2087: 123 (or, alternatively, any of the other patterns of length 3); that is, the number of permutations with no three-term increasing subsequence. For 1291:{\displaystyle C_{n}={\frac {1}{2\pi }}\int _{0}^{4}x^{n}{\sqrt {\frac {4-x}{x}}}\,dx\,={\frac {2}{\pi }}4^{n}\int _{-1}^{1}t^{2n}{\sqrt {1-t^{2}}}\,dt.} 951: 10691: 10382: 8465:{\displaystyle \det {\begin{bmatrix}1&2&5&14\\2&5&14&42\\5&14&42&132\\14&42&132&429\end{bmatrix}}=1.} 276:{\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}=\prod \limits _{k=2}^{n}{\frac {n+k}{k}}\qquad {\text{for }}n\geq 0.} 7400:
if, reading from left to right, the number of X's is always strictly greater than the number of Y's. The cycle lemma states that any sequence of
8294:{\displaystyle \det {\begin{bmatrix}1&1&2&5\\1&2&5&14\\2&5&14&42\\5&14&42&132\end{bmatrix}}=1.} 2191:
rectangles. Cutting across the anti-diagonal and looking at only the edges gives full binary trees. The following figure illustrates the case
4715: 8553: 6670: 1880:
The dark triangle is the root node, the light triangles correspond to internal nodes of the binary trees, and the green bars are the leaves.
464: 2228:
downstrokes that all stay above a horizontal line. The mountain range interpretation is that the mountains will never go below the horizon.
10399: 5063:
edges above the diagonal. For example, in Figure 2, the edges above the diagonal are marked in red, so the exceedance of this path is 5.
7979: 5256: 1432: 12796: 10814: 307: 5610:
whose side is marked (in two ways, and subtract the two that cannot collapse the base), or, in reverse, expand the oriented edge in
10852: 5917: 1606:
Y's such that no initial segment of the string has more Y's than X's. For example, the following are the Dyck words up to length 6:
1304: 5706: 5066:
Given a monotonic path whose exceedance is not zero, we apply the following algorithm to construct a new path whose exceedance is
1066: 7206: 7022:{\displaystyle B_{n+1}-C_{n+1}=2\sum _{i=0}^{n}B_{i}C_{n-i}-\sum _{i=0}^{n}C_{i}\,C_{n-i}=\sum _{i=0}^{n}(2B_{i}-C_{i})C_{n-i}.} 595: 12786: 10831: 10727: 10674: 10607: 9993: 1035: 8505: 7305: 6512: 3287: 336: 5791: 3001: 11659: 10845: 3533: 3465: 1703:((ab)c)d     (a(bc))d     (ab)(cd)     a((bc)d)     a(b(cd)) 12791: 11654: 8860:, who was interested in the number of different ways of dividing a polygon into triangles. The sequence is named after 7548:
X's. Each of these X's was the start of a dominating circular shift before anything was removed. For example, consider
2704:
rectangle so that each row and each column is increasing. As such, the formula can be derived as a special case of the
9057: 11669: 10654: 10038: 7124: 7042: 6387: 3436:. On the one hand, the recurrence relation uniquely determines the Catalan numbers; on the other hand, interpreting 11649: 10821: 10493:
Choi, Hayoung; Yeh, Yeong-Nan; Yoo, Seonguk (2020), "Catalan-like number sequences and Hausdorff moment sequences",
10105:
Choi, Hayoung; Yeh, Yeong-Nan; Yoo, Seonguk (2020), "Catalan-like number sequences and Hausdorff moment sequences",
10023: 9148: 12362: 11942: 10468:
and Nathan Reading, "Root systems and generalized associahedra", Geometric combinatorics, IAS/Park City Math. Ser.
9206:, the numbers have an easy combinatorial description. However, other combinatorial descriptions are only known for 4530: 9272:, it is the number of anti-chains (or order ideals) in the poset of positive roots. The classical Catalan number 7852: 5358: 4515:{\displaystyle c(x)={\frac {1-{\sqrt {1-4x}}}{2x}}=\sum _{n=0}^{\infty }{\frac {1}{n+1}}{\binom {2n}{n}}x^{n}\,.} 1650:((()))     (()())     (())()     ()(())     ()()() 4539:
Figure 1. The invalid portion of the path (dotted red) is flipped (solid red). Bad paths (after the flip) reach
3608: 1806: 11664: 5210: 3216:{\displaystyle C_{0}=1\quad {\text{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0.} 6318:{\displaystyle C_{0}=1\quad {\text{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0} 5623: 1621:
XXXYYY     XYXXYY     XYXYXY     XXYYXY     XXYXYY
12448: 10473: 5606:
There is a simple bijection between these two marked triangulations: We can either collapse the triangle in
10252: 10232:
A. de Segner, Enumeratio modorum, quibus figurae planae rectilineae per diagonales dividuntur in triangula.
5100:
In Figure 3, the black dot indicates the point where the path first crosses the diagonal. The black edge is
938:{\displaystyle C_{0}=1\quad {\text{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1}\quad {\text{for }}n>0.} 12114: 11764: 11433: 11226: 9963: 9493: 9010: 8876: 2705: 810:{\displaystyle C_{0}=1\quad {\text{and}}\quad C_{n}=\sum _{i=1}^{n}C_{i-1}C_{n-i}\quad {\text{for }}n>0} 94: 12290: 12149: 11980: 11794: 11784: 11438: 11418: 10664: 9978: 1688: 1039: 12119: 10158:
Feng, Qi; Bai-Ni, Guo (2017), "Integral Representations of the Catalan Numbers and Their Applications",
3084:; they involve literally counting a collection of some kind of object to arrive at the correct formula. 582:, which is not immediately obvious from the first formula given. This expression forms the basis for a 12781: 12239: 11862: 11704: 11619: 11428: 11410: 11304: 11294: 11284: 11120: 10719: 10043: 8697:{\displaystyle \det {\begin{bmatrix}2&5&14\\5&14&42\\14&42&132\end{bmatrix}}=4} 7695: 7659: 7623: 7587: 7551: 4595: 3369: 3363:
The recurrence relation given above can then be summarized in generating function form by the relation
1973: 12144: 5167:
on the diagonal. Alternatively, reverse the original algorithm to look for the first edge that passes
12367: 11912: 11533: 11319: 11314: 11309: 11299: 11276: 9264:
and Nathan Reading have given a generalized Catalan number associated to any finite crystallographic
1595: 1429:. Since the 1D random walk is recurrent, the probability that the walker eventually arrives at -1 is 12124: 10445:
Gheorghiciuc, Irina; Orelowitz, Gidon (2020). "Super-Catalan Numbers of the Third and Fourth Kind".
8937: 8902: 8861: 6127: 1795: 79: 11789: 11699: 11352: 9330: 8972: 3459:, the generating function relation can be algebraically solved to yield two solution possibilities 7390: 12478: 12443: 12229: 12139: 12013: 11988: 11897: 11887: 11609: 11499: 11481: 11401: 10745: 9988: 5435: 2101:, they are 1432, 2143, 2413, 2431, 3142, 3214, 3241, 3412, 3421, 4132, 4213, 4231, 4312 and 4321. 10638: 10632: 10360:
Stanley, Richard P. (2021). "Enumerative and Algebraic Combinatorics in the 1960's and 1970's".
10286: 5511:
This proof uses the triangulation definition of Catalan numbers to establish a relation between
3432:
in other words, this equation follows from the recurrence relation by expanding both sides into
431: 12738: 12008: 11882: 11513: 11289: 11069: 10996: 10403: 4642:
path crosses the main diagonal and touches the next higher diagonal (red in the illustration).
1953: 1709: 10820:"Equivalence of Three Catalan Number Interpretations" from The Wolfram Demonstrations Project 5135:
Figure 4. All monotonic paths in a 3×3 grid, illustrating the exceedance-decreasing algorithm.
12702: 12342: 11993: 11847: 11774: 10929: 10699: 10064: 9973: 6039: 3093: 2115: 1905: 40: 20: 10682:
Koshy, Thomas & Zhenguang Gao (2011) "Some divisibility properties of Catalan numbers",
7443: 12635: 12529: 12493: 12234: 11957: 11937: 11754: 11423: 11211: 10737: 10683: 10642: 10524: 10136: 10013: 9302: 9275: 9268:, namely the number of fully commutative elements of the group; in terms of the associated 9209: 9016: 8864:, who discovered the connection to parenthesized expressions during his exploration of the 7820: 6475: 6176: 6084: 5404: 2718: 1405: 11714: 11183: 8869: 7950: 6446: 2969: 2389: 2317: 2279: 2241: 1376: 8: 12357: 12221: 12216: 12184: 11947: 11922: 11917: 11892: 11822: 11818: 11749: 11639: 11471: 11267: 11236: 9183: 9157: 8065: 7904: 7774: 7525: 7499: 7469: 5548:
sides and a triangulation, mark one of its sides as the base, and also orient one of its
5480: 5074:
Starting from the bottom left, follow the path until it first travels above the diagonal.
5044:. A generalized version of this proof can be found in a paper of Rukavicka Josef (2011). 3278: 3096: 3077: 2829: 2127: 2084: 1742: 691: 10646: 6604: 5159:, which originally was the first horizontal step ending on the diagonal, has become the 1045: 12760: 12514: 12509: 12423: 12397: 12295: 12274: 12046: 11927: 11877: 11799: 11769: 11709: 11476: 11456: 11387: 11100: 10762: 10578: 10558: 10528: 10502: 10477: 10446: 10425: 10361: 10186: 10140: 10114: 10087: 9968: 9949: 9241: 8091: 7930: 7800: 7754: 7734: 7423: 7403: 6647: 6627: 6367: 6347: 3448: 2963: 2809: 2789: 2769: 2749: 1760: 1523: 47: 11644: 10346: 10018: 2686: 1698:, for example, we have the following five different parenthesizations of four factors: 12756: 12654: 12599: 12453: 12428: 12402: 11857: 11852: 11779: 11759: 11744: 11466: 11448: 11367: 11357: 11342: 11105: 10796: 10723: 10670: 10650: 10603: 10532: 10277: 10144: 9943: 7771:
Y's if and only if prepending an X to the Dyck word gives a dominating sequence with
5000:{\displaystyle C_{n}={2n \choose n}-{2n \choose n+1}={\frac {1}{n+1}}{2n \choose n}.} 3456: 2943:{\displaystyle 1234,1233,1232,1231,1223,1222,1221,1212,1211,1123,1122,1121,1112,1111} 12179: 10582: 7817:
Y's, so we can count the former by instead counting the latter. In particular, when
5047: 3602:
From the two possibilities, the second must be chosen because only the second gives
12690: 12483: 12069: 12041: 12031: 12023: 11907: 11872: 11867: 11834: 11528: 11491: 11382: 11377: 11372: 11362: 11334: 11221: 11168: 11125: 11064: 10799: 10568: 10512: 10342: 10309: 10281: 10273: 10208: 10167: 10124: 10079: 2962:. Record the values at only the X's. Compared to the similar representation of the 11173: 10313: 5107: 1866: 12666: 12555: 12488: 12414: 12337: 12311: 12129: 11842: 11634: 11604: 11594: 11589: 11255: 11163: 11110: 10954: 10894: 10733: 10520: 10424:
Chen, Xin; Wang, Jane (2012). "The super Catalan numbers S(m, m + s) for s ≀ 4".
10327: 10132: 10008: 9983: 8868:
puzzle. The reflection counting trick (second proof) for Dyck words was found by
8865: 5131: 4535: 3674: 3081: 1684: 12671: 12539: 12524: 12388: 12352: 12327: 12203: 12174: 12159: 12036: 11932: 11902: 11629: 11461: 11059: 11054: 11049: 11021: 11006: 10919: 10904: 10882: 10869: 10783: 10628: 10617: 10613: 10516: 10128: 10033: 10003: 8857: 8844: 7493: 5203:
equally sized classes, corresponding to the possible exceedances between 0 and
1886: 67: 10573: 10546: 5432:
that brings an initial subsequence to equality, and configure the sequence as
1708:
Successive applications of a binary operator can be represented in terms of a
12775: 12594: 12578: 12519: 12473: 12169: 12154: 12064: 11347: 11216: 11178: 11135: 11016: 11001: 10991: 10949: 10939: 10914: 10837: 9958: 9265: 8899:
For instance, Ming used the Catalan sequence to express series expansions of
8126: 8108:
Y's that are dominating, each of which corresponds to exactly one Dyck word.
7386: 6078: 3092:
We first observe that all of the combinatorial problems listed above satisfy
3076:
solves the combinatorial problems listed above. The first proof below uses a
1772: 1677: 1627: 1515: 55: 9258:, and it is an open problem to find a general combinatorial interpretation. 8882:
In 1988, it came to light that the Catalan number sequence had been used in
12630: 12619: 12534: 12372: 12347: 12264: 12164: 12134: 12109: 12093: 11998: 11965: 11688: 11599: 11538: 11115: 11011: 10944: 10924: 10899: 10465: 9998: 9261: 3433: 1934: 1901: 1876: 1838: 1824:
for a sentence (assuming binary branching), in natural language processing.
28: 10264:
Dershowitz, Nachum; Zaks, Shmuel (1980), "Enumerations of ordered trees",
8475:
Taken together, these two conditions uniquely define the Catalan numbers.
1873:
This can be represented by listing the Catalan elements by column height:
12589: 12464: 12269: 11733: 11624: 11579: 11574: 11324: 11231: 11130: 10959: 10934: 10909: 10300:
Dvoretzky, Aryeh; Motzkin, Theodore (1947), "A problem of arrangements",
10209:"An efficient representation for solving Catalan number related problems" 9269: 8158: 2148: 1957: 684: 71: 44: 10826: 10172: 10091: 8850:
The Quick Method for Obtaining the Precise Ratio of Division of a Circle
1767: 12726: 12707: 12003: 11614: 10547:"Counting symmetry: classes of dissections of a convex regular polygon" 9144: 5192:, and so on, down to zero. In other words, we have split up the set of 4848:{\displaystyle {n-1+n+1 \choose n-1}={2n \choose n-1}={2n \choose n+1}} 4567:
We count the number of paths which start and end on the diagonal of an
2202: 1821: 78:
defined objects. They are named after the French-Belgian mathematician
8605:{\displaystyle \det {\begin{bmatrix}2&5\\5&14\end{bmatrix}}=3} 6785:{\displaystyle B_{n+1}-C_{n+1}=\sum _{i=0}^{n}{2i+1 \choose i}C_{n-i}} 5352:, and the last column displays all paths no higher than the diagonal. 1027:-th Catalan number and the expression on the right tends towards 1 as 560:{\displaystyle {\tbinom {2n}{n+1}}={\tfrac {n}{n+1}}{\tbinom {2n}{n}}} 12332: 12259: 12251: 12056: 11970: 11088: 10804: 10713: 10481: 10083: 10028: 7522:
X's and Y's in a circle. Repeatedly removing XY pairs leaves exactly
1584: 75: 6112:
pairs of brackets. We denote a (possibly empty) correct string with
12433: 10767: 10507: 10451: 10366: 10119: 8887: 3230:
of length â‰„ 2 can be written in a unique way in the form
1897: 1016:{\displaystyle C_{n}\sim {\frac {4^{n}}{n^{3/2}{\sqrt {\pi }}}}\,,} 83: 63: 10563: 10430: 8055:{\displaystyle \textstyle {\frac {1}{2n+1}}{2n+1 \choose n}=C_{n}} 1549: 12438: 12097: 12091: 5026:
This bijective proof provides a natural explanation for the term
3673:
The square root term can be expanded as a power series using the
1673: 579: 9009:
The Catalan numbers can be interpreted as a special case of the
8478:
Another feature unique to the Catalan–Hankel matrix is that the
6443:. A balanced string can also be uniquely decomposed into either 5326:{\displaystyle \textstyle C_{n}={\frac {1}{n+1}}{2n \choose n}.} 2693:
rectangle. In other words, it is the number of ways the numbers
1499:{\displaystyle \sum _{n=0}^{\infty }{\frac {C_{n}}{2^{2n+1}}}=1} 10400:"Ming Antu, the First Inventor of Catalan Numbers in the World" 9180:, this is just two times the ordinary Catalan numbers, and for 7584:. This sequence is dominating, but none of its circular shifts 5010:
In terms of Dyck words, we start with a (non-Dyck) sequence of
11153: 10250:
On Generalized Dyck Paths, Electronic Journal of Combinatorics
5155:
when the algorithm is applied to it. Indeed, the (black) edge
5123:. In fact, the algorithm causes the exceedance to decrease by 1912:
and the number of different ways that this can be achieved is
8883: 6026:{\displaystyle {\frac {(2n)!}{n!}}=2^{n}(2n-1)!!=(4n-2)!!!!.} 1362:{\displaystyle \sum _{n=0}^{\infty }{\frac {C_{n}}{4^{n}}}=2} 93:-th Catalan number can be expressed directly in terms of the 9139:
is a generalization of the Catalan numbers. These are named
8332:
then the determinant is still 1, regardless of the value of
7849:, there is exactly one dominating circular shift. There are 5776:{\displaystyle \textstyle {\frac {4n-2}{n+1}}C_{n-1}=C_{n}.} 10718:, Cambridge Studies in Advanced Mathematics, vol. 62, 10692:"The 18th century Chinese discovery of the Catalan numbers" 10383:"The 18th century Chinese discovery of the Catalan numbers" 9918: 1090:; all others are even. The only prime Catalan numbers are 302: 298:
1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786, ...
8856:
The Catalan sequence was described in the 18th century by
7292:{\displaystyle C_{i}=2{\binom {2i}{i}}-{\binom {2i+1}{i}}} 2183:
is the number of ways to tile a stairstep shape of height
2094:, these permutations are 132, 213, 231, 312 and 321. For 673:{\displaystyle C_{n}={\frac {1}{2n+1}}{2n+1 \choose n}\,,} 461:
which is equivalent to the expression given above because
9151:, which sometimes are also called super-Catalan numbers. 7713: 7710: 7707: 7704: 7677: 7674: 7671: 7668: 7641: 7638: 7635: 7632: 7605: 7602: 7599: 7596: 7569: 7566: 7563: 7560: 5111:
Figure 3. The green and red portions are being exchanged.
1518:
whose solution is given by the Catalan numbers. The book
82:, though they were previously discovered in the 1730s by 6601:
Any incorrect (non-Catalan) balanced string starts with
2712:
123 124 125 134 135 456 356 346 256 246
2162:
is also the number of noncrossing partitions of the set
10794: 10785:
Catalan addendum to Enumerative Combinatorics, Volume 2
9329:
The Catalan numbers are a solution of a version of the
8722: 8630: 8565: 8540:{\displaystyle \det {\begin{bmatrix}2\end{bmatrix}}=2} 8517: 8361: 8190: 7983: 7856: 7370:{\displaystyle C_{i}={\frac {1}{i+1}}{\binom {2i}{i}}} 6391: 5710: 5362: 5260: 5214: 5185:, which is equal to the number of paths of exceedance 4600: 4531:
Method of images § Mathematics for discrete cases
2220:
is the number of ways to form a "mountain range" with
1113:
The Catalan numbers have the integral representations
1036:
asymptotic growth of the central binomial coefficients
529: 509: 469: 11817: 10756: 10444: 10234:
Novi commentarii academiae scientiarum Petropolitanae
10216:
International Journal of Pure and Applied Mathematics
9692: 9497: 9364: 9305: 9278: 9244: 9212: 9186: 9160: 9060: 9019: 8975: 8940: 8905: 8713: 8621: 8556: 8508: 8352: 8181: 8094: 8068: 7982: 7953: 7933: 7907: 7855: 7823: 7803: 7777: 7757: 7737: 7698: 7662: 7626: 7590: 7554: 7528: 7502: 7472: 7446: 7426: 7406: 7308: 7209: 7127: 7045: 6804: 6673: 6650: 6630: 6607: 6591:{\displaystyle B_{n+1}=2\sum _{i=0}^{n}B_{i}C_{n-i}.} 6515: 6478: 6449: 6390: 6370: 6350: 6209: 6179: 6130: 6087: 6042: 5920: 5794: 5709: 5626: 5483: 5438: 5407: 5361: 5259: 5213: 5033:
appearing in the denominator of the formula for 
4867: 4718: 4598: 4377: 3684: 3611: 3536: 3468: 3372: 3353:{\displaystyle c(x)=\sum _{n=0}^{\infty }C_{n}x^{n}.} 3290: 3107: 3004: 2995:
There are several ways of explaining why the formula
2972: 2858: 2832: 2812: 2792: 2772: 2752: 2721: 2392: 2320: 2282: 2244: 1435: 1408: 1379: 1307: 1122: 1048: 954: 829: 702: 598: 467: 434: 421:{\displaystyle C_{n}={2n \choose n}-{2n \choose n+1}} 339: 106: 12202: 9939: 9054:
The two-parameter sequence of non-negative integers
7976:
circular shifts is dominating. Therefore there are
5901:{\displaystyle (2n)!=(2n)!!(2n-1)!!=2^{n}n!(2n-1)!!} 5174:
This implies that the number of paths of exceedance
3066:{\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}} 8890:by 1730. That is when he started to write his book 8304:Moreover, if the indexing is "shifted" so that the 7389:interpretation of the Catalan numbers and uses the 3591:{\displaystyle c(x)={\frac {1-{\sqrt {1-4x}}}{2x}}} 3523:{\displaystyle c(x)={\frac {1+{\sqrt {1-4x}}}{2x}}} 10759:Super-Catalan Numbers of the Third and Fourth Kind 9924: 9318: 9291: 9250: 9230: 9198: 9172: 9131: 9032: 8993: 8961: 8926: 8825: 8696: 8604: 8539: 8464: 8293: 8100: 8080: 8054: 7968: 7939: 7919: 7893: 7841: 7809: 7789: 7763: 7743: 7720: 7684: 7648: 7612: 7576: 7540: 7514: 7484: 7458: 7432: 7412: 7369: 7291: 7192: 7110: 7021: 6784: 6656: 6636: 6616: 6590: 6498: 6464: 6435: 6376: 6356: 6317: 6192: 6165: 6100: 6061: 6025: 5900: 5775: 5691: 5495: 5469: 5420: 5393: 5325: 5245: 4999: 4847: 4630: 4514: 4363: 3661: 3590: 3522: 3421: 3352: 3215: 3065: 2978: 2942: 2844: 2818: 2798: 2778: 2758: 2734: 2407: 2335: 2297: 2259: 1498: 1421: 1394: 1361: 1290: 1057: 1015: 937: 809: 683:which can be directly interpreted in terms of the 672: 559: 450: 420: 275: 11201: 10326:Dershowitz, Nachum; Zaks, Shmuel (January 1990). 7361: 7343: 7283: 7259: 7247: 7229: 7184: 7160: 7102: 7078: 6760: 6736: 4988: 4970: 4940: 4914: 4902: 4884: 4839: 4813: 4801: 4775: 4763: 4722: 4492: 4474: 4331: 4313: 3768: 3745: 3057: 3039: 1645:pairs of parentheses which are correctly matched: 660: 636: 412: 386: 374: 356: 159: 141: 12773: 10634:Time Travel and Other Mathematical Bewilderments 10299: 9132:{\displaystyle {\frac {(2m)!(2n)!}{(m+n)!m!n!}}} 8714: 8622: 8557: 8509: 8353: 8182: 3626: 1509: 11087: 10637:, New York: W.H. Freeman and Company, pp.  10206: 7193:{\displaystyle C_{i}=2B_{i}-{\binom {2i+1}{i}}} 7111:{\displaystyle 2B_{i}-C_{i}={\binom {2i+1}{i}}} 6436:{\displaystyle \textstyle B_{n}={2n \choose n}} 5253:monotonic paths, we obtain the desired formula 43:of a 5-element set (below, the other 10 of the 10881: 10867: 10757:Gheorghiciuc, Irina; Orelowitz, Gidon (2020), 10325: 10263: 5178:is equal to the number of paths of exceedance 5088:Swap the portion of the path occurring before 10853: 10062: 9336: 9040:is the number of ways for a candidate A with 8032: 8008: 7884: 7860: 7496:. To see this, arrange the given sequence of 6426: 6408: 5603:such marked triangulations for a given base. 5572:such marked triangulations for a given base. 5384: 5366: 5355:Using Dyck words, start with a sequence from 5313: 5295: 5236: 5218: 4621: 4603: 2062:being the identity for one-element sequences. 1923:. The following hexagons illustrate the case 550: 532: 498: 472: 12689: 11039: 5335:Figure 4 illustrates the situation for  1641:counts the number of expressions containing 948:Asymptotically, the Catalan numbers grow as 10544: 8875:The name “Catalan numbers” originated from 7894:{\displaystyle \textstyle {2n+1 \choose n}} 6200:immediately gives the recursive definition 5394:{\displaystyle \textstyle {\binom {2n}{n}}} 5059:of the path is defined to be the number of 4585:up steps. Since we can choose which of the 1553:Lattice of the 14 Dyck words of length 8 – 11154:Possessing a specific set of other numbers 10977: 10860: 10846: 10492: 10157: 10104: 10063:Koshy, Thomas; Salmassi, Mohammad (2006). 6081:interpretation of the Catalan numbers, so 4592:steps are up or right, there are in total 3662:{\displaystyle C_{0}=\lim _{x\to 0}c(x)=1} 1752:leaves, or, equivalently, with a total of 12617: 11564: 10766: 10743: 10572: 10562: 10506: 10450: 10429: 10365: 10285: 10171: 10118: 10065:"Parity and primality of Catalan numbers" 7947:Y's. For each of these, only one of the 6927: 6283: 6108:is the number of ways to correctly match 5246:{\displaystyle \textstyle {2n \choose n}} 5151:, there is exactly one path which yields 4508: 4353: 3181: 2806:, or decrease by any number (to at least 2002:is defined recursively as follows: write 1900:by connecting vertices with non-crossing 1278: 1203: 1196: 1009: 666: 444: 206: 10689: 10624:. New York: Copernicus, pp. 96–106. 10423: 10417: 8843: 8316:entry is filled with the Catalan number 6624:, and the remaining string has one more 5692:{\displaystyle (4n+2)C_{n}=(n+2)C_{n+1}} 5130: 5106: 5046: 4682:, all bad paths after reflection end at 4534: 1875: 1766: 1626:Re-interpreting the symbol X as an open 1548: 27: 10781: 10747:A Catalan–Hankel Determinant Evaluation 10711: 10627: 10359: 10328:"The Cycle Lemma and Some Applications" 10207:ČrepinĆĄek, Matej; Mernik, Luka (2009). 9299:corresponds to the root system of type 6173:, summing over the possible lengths of 2990: 2950:. From a Dyck path, start a counter at 584:proof of the correctness of the formula 12774: 12725: 9147:. These should not confused with the 4709:The number of bad paths is therefore: 4694:. Because every monotonic path in the 4670:right steps. So, instead of reaching 3281:for the Catalan numbers is defined by 1807:encoding general trees as binary trees 1023:in the sense that the quotient of the 12724: 12688: 12652: 12616: 12576: 12201: 12090: 11816: 11731: 11686: 11563: 11253: 11200: 11152: 11086: 11038: 10976: 10880: 10841: 10795: 10662: 9994:List of factorial and binomial topics 6795:Also, from the definitions, we have: 5614:to a triangle and mark its new side. 5077:Continue to follow the path until it 1908:). The number of triangles formed is 1856:The following diagrams show the case 11254: 10380: 5139:It can be seen that this process is 5085:the first such edge that is reached. 1514:There are many counting problems in 12653: 10476:, Providence, RI, 2007, pp 63–131. 8848:Catalan numbers in Mingantu's book 7032:Therefore, as this is true for all 5070:less than the one we started with. 5051:Figure 2. A path with exceedance 5. 3080:. The other proofs are examples of 1779:=14 full binary trees with 5 leaves 1520:Enumerative Combinatorics: Volume 2 220: 13: 12577: 10832:Partition related number triangles 9370: 9004: 8012: 7864: 7701: 7665: 7629: 7593: 7557: 7396:We call a sequence of X's and Y's 7347: 7263: 7233: 7164: 7082: 6740: 6412: 5370: 5299: 5222: 4974: 4918: 4888: 4817: 4779: 4726: 4607: 4478: 4448: 4317: 4287: 4197: 4084: 3947: 3818: 3749: 3737: 3322: 3043: 2201: 2170:in which every block is of size 2. 1933: 1865: 1759: 1452: 1324: 640: 589:Another alternative expression is 536: 476: 390: 360: 145: 14: 12808: 10775: 10715:Enumerative combinatorics. Vol. 2 10666:Catalan Numbers with Applications 10335:European Journal of Combinatorics 7721:{\displaystyle {\mathit {YXXYX}}} 7685:{\displaystyle {\mathit {XYXXY}}} 7649:{\displaystyle {\mathit {YXYXX}}} 7613:{\displaystyle {\mathit {XYXYX}}} 7577:{\displaystyle {\mathit {XXYXY}}} 5092:with the portion occurring after 4631:{\displaystyle {\tbinom {2n}{n}}} 3422:{\displaystyle c(x)=1+xc(x)^{2};} 3256:with (possibly empty) Dyck words 2075:is the number of permutations of 1373:arrive at the trap state at time 1083:that are odd are those for which 583: 12797:Eponymous numbers in mathematics 12755: 12363:Perfect digit-to-digit invariant 11732: 10825: 10545:Bowman, D.; Regev, Alon (2014). 9942: 8111: 6124:can be uniquely decomposed into 5115:The exceedance has dropped from 4638:monotonic paths of this type. A 2954:. An X increases the counter by 1794:is the number of non-isomorphic 1665:is the number of different ways 1034:This can be proved by using the 690:The Catalan numbers satisfy the 10538: 10486: 10459: 10438: 10392: 10374: 10353: 10319: 10293: 10072:The College Mathematics Journal 9047:votes to lead candidate B with 8886:by the Mongolian mathematician 6333:be a balanced string of length 6300: 6232: 6226: 5506: 4524: 3198: 3130: 3124: 2028:are shorter sequences, and set 1841:along the edges of a grid with 920: 852: 846: 792: 725: 719: 258: 10830:Learning materials related to 10602:. Cambridge University Press, 10287:2027/uiuo.ark:/13960/t3kw6z60d 10257: 10242: 10226: 10200: 10191: 10180: 10151: 10098: 10056: 9889: 9877: 9859: 9847: 9841: 9824: 9812: 9803: 9800: 9789: 9777: 9768: 9763: 9752: 9740: 9731: 9725: 9713: 9710: 9698: 9643: 9631: 9625: 9599: 9596: 9570: 9562: 9536: 9530: 9518: 9515: 9503: 9108: 9096: 9088: 9079: 9073: 9064: 8988: 8982: 8962:{\displaystyle \sin(4\alpha )} 8956: 8947: 8927:{\displaystyle \sin(2\alpha )} 8921: 8912: 8161:1, regardless of the value of 7380: 6997: 6968: 6651: 6631: 6611: 6490: 6479: 6456: 6450: 6371: 6351: 6166:{\displaystyle c=(c_{1})c_{2}} 6150: 6137: 6072: 6005: 5990: 5978: 5963: 5933: 5924: 5889: 5874: 5846: 5831: 5822: 5813: 5804: 5795: 5670: 5658: 5642: 5627: 5464: 5458: 5445: 5439: 5147:whose exceedance is less than 5081:the diagonal again. Denote by 5021: 4387: 4381: 4237: 4225: 4217: 4208: 4146: 4134: 4123: 4108: 4050: 4037: 4028: 4016: 3989: 3974: 3965: 3955: 3909: 3896: 3866: 3851: 3836: 3826: 3787: 3774: 3650: 3644: 3633: 3546: 3540: 3478: 3472: 3407: 3400: 3382: 3376: 3300: 3294: 3087: 1630:and Y as a close parenthesis, 887: 872: 567:. This expression shows that 319:An alternative expression for 286:The first Catalan numbers for 200: 188: 180: 171: 1: 12787:Factorial and binomial topics 11202:Expressible via specific sums 10592: 10474:American Mathematical Society 10347:10.1016/S0195-6698(13)80053-4 10314:10.1215/s0012-7094-47-01423-3 10039:Wedderburn–Etherington number 8994:{\displaystyle \sin(\alpha )} 3226:For example, every Dyck word 2766:, and can increase by either 2231: 1741:is the number of full binary 1510:Applications in combinatorics 314: 95:central binomial coefficients 10782:Stanley, Richard P. (1998), 10712:Stanley, Richard P. (1999), 10598:Stanley, Richard P. (2015), 10278:10.1016/0012-365x(80)90168-5 8141:entry is the Catalan number 6344:contains an equal number of 6036:Applying the recursion with 5055:Given a monotonic path, the 1616:XXYY     XYXY 7: 12291:Multiplicative digital root 10669:, Oxford University Press, 9935: 9149:Schröder–Hipparchus numbers 7731:A string is a Dyck word of 7385:This proof is based on the 6077:This proof is based on the 5470:{\displaystyle (F)X_{d}(L)} 2746:sequences that start with 1837:is the number of monotonic 1689:matrix chain multiplication 10: 12813: 11687: 10720:Cambridge University Press 10517:10.1016/j.disc.2019.111808 10129:10.1016/j.disc.2019.111808 10024:Schröder–Hipparchus number 9337:Catalan k-fold convolution 8839: 7393:of Dvoretzky and Motzkin. 4577:grid. All such paths have 4528: 2700:can be arranged in a 2-by- 2016:is the largest element in 1820:is the number of possible 1676:(or the number of ways of 1672:factors can be completely 451:{\displaystyle n\geq 0\,,} 18: 16:Recursive integer sequence 12792:Enumerative combinatorics 12751: 12734: 12720: 12698: 12684: 12662: 12648: 12626: 12612: 12585: 12572: 12548: 12502: 12462: 12413: 12387: 12368:Perfect digital invariant 12320: 12304: 12283: 12250: 12215: 12211: 12197: 12105: 12086: 12055: 12022: 11979: 11956: 11943:Superior highly composite 11833: 11829: 11812: 11740: 11727: 11695: 11682: 11570: 11559: 11521: 11512: 11490: 11447: 11409: 11400: 11333: 11275: 11266: 11262: 11249: 11207: 11196: 11159: 11148: 11096: 11082: 11045: 11034: 10987: 10972: 10890: 10876: 10574:10.1016/j.aam.2014.01.004 10302:Duke Mathematical Journal 10197:Stanley p.221 example (e) 9964:Bertrand's ballot theorem 9345:-fold convolution, where 9011:Bertrand's ballot theorem 1301:which immediately yields 1072:The only Catalan numbers 56:combinatorial mathematics 11981:Euler's totient function 11765:Euler–Jacobi pseudoprime 11040:Other polynomial numbers 10744:Egecioglu, Omer (2009), 10248:Rukavicka Josef (2011), 10050: 9331:Hausdorff moment problem 2958:and a Y decreases it by 2742:is the number of length 2689:whose diagram is a 2-by- 1796:ordered (or plane) trees 1712:, by labeling each leaf 1067:via generating functions 1040:Stirling's approximation 19:Not to be confused with 11795:Somer–Lucas pseudoprime 11785:Lucas–Carmichael number 11620:Lazy caterer's sequence 10690:Larcombe, P.J. (1999). 10044:Wigner's semicircle law 9979:Catalan–Mersenne number 7901:sequences with exactly 6062:{\displaystyle C_{0}=1} 5556:total edges. There are 2687:standard Young tableaux 1852:Y stands for "move up". 11670:Wedderburn–Etherington 11070:Lucky numbers of Euler 10817:. Still more examples. 10663:Koshy, Thomas (2008), 9926: 9320: 9293: 9252: 9232: 9200: 9174: 9133: 9034: 8995: 8963: 8928: 8862:EugĂšne Charles Catalan 8853: 8827: 8698: 8606: 8541: 8488:submatrix starting at 8466: 8295: 8102: 8082: 8062:distinct sequences of 8056: 7970: 7941: 7921: 7895: 7843: 7811: 7791: 7765: 7745: 7722: 7686: 7650: 7614: 7578: 7542: 7516: 7486: 7460: 7459:{\displaystyle m>n} 7434: 7414: 7371: 7293: 7194: 7112: 7023: 6967: 6916: 6866: 6786: 6732: 6658: 6638: 6618: 6592: 6558: 6500: 6466: 6437: 6378: 6358: 6319: 6272: 6194: 6167: 6102: 6063: 6027: 5902: 5777: 5693: 5497: 5477:. The new sequence is 5471: 5422: 5395: 5327: 5247: 5136: 5112: 5052: 5001: 4849: 4649:Since there are still 4632: 4564: 4516: 4452: 4365: 4291: 4201: 4088: 3951: 3822: 3741: 3663: 3592: 3524: 3423: 3354: 3326: 3217: 3170: 3067: 2980: 2944: 2846: 2820: 2800: 2780: 2760: 2736: 2409: 2337: 2299: 2261: 2206: 2116:noncrossing partitions 1938: 1896:sides can be cut into 1881: 1870: 1780: 1764: 1569: 1500: 1456: 1423: 1396: 1363: 1328: 1292: 1059: 1017: 939: 811: 759: 674: 561: 452: 422: 277: 239: 80:EugĂšne Charles Catalan 70:that occur in various 51: 41:noncrossing partitions 11958:Prime omega functions 11775:Frobenius pseudoprime 11565:Combinatorial numbers 11434:Centered dodecahedral 11227:Primary pseudoperfect 10700:Mathematical Spectrum 9927: 9321: 9319:{\displaystyle A_{n}} 9294: 9292:{\displaystyle C_{n}} 9253: 9233: 9231:{\displaystyle m=2,3} 9201: 9175: 9141:super-Catalan numbers 9134: 9035: 9033:{\displaystyle C_{n}} 8996: 8964: 8929: 8847: 8828: 8699: 8607: 8542: 8467: 8296: 8103: 8083: 8057: 7971: 7942: 7922: 7896: 7844: 7842:{\displaystyle m=n+1} 7812: 7792: 7766: 7746: 7723: 7687: 7651: 7615: 7579: 7543: 7517: 7487: 7461: 7435: 7415: 7372: 7294: 7195: 7113: 7024: 6947: 6896: 6846: 6787: 6712: 6659: 6639: 6619: 6593: 6538: 6501: 6499:{\displaystyle )c'(b} 6467: 6438: 6379: 6359: 6320: 6252: 6195: 6193:{\displaystyle c_{1}} 6168: 6116:and its inverse with 6103: 6101:{\displaystyle C_{n}} 6064: 6028: 5903: 5778: 5694: 5498: 5472: 5423: 5421:{\displaystyle X_{d}} 5396: 5328: 5248: 5196:monotonic paths into 5134: 5110: 5050: 5002: 4850: 4656:steps, there are now 4633: 4538: 4517: 4432: 4366: 4271: 4181: 4068: 3931: 3802: 3721: 3664: 3593: 3525: 3424: 3355: 3306: 3218: 3150: 3068: 2981: 2945: 2847: 2821: 2801: 2781: 2761: 2737: 2735:{\displaystyle C_{n}} 2410: 2338: 2300: 2262: 2205: 1937: 1906:polygon triangulation 1879: 1869: 1775:of order 4 with the C 1770: 1763: 1552: 1501: 1436: 1424: 1422:{\displaystyle C_{k}} 1397: 1364: 1308: 1293: 1060: 1031:approaches infinity. 1018: 940: 812: 739: 675: 562: 453: 423: 278: 219: 31: 12417:-composition related 12217:Arithmetic functions 11819:Arithmetic functions 11755:Elliptic pseudoprime 11439:Centered icosahedral 11419:Centered tetrahedral 10684:Mathematical Gazette 10495:Discrete Mathematics 10266:Discrete Mathematics 10107:Discrete Mathematics 10014:Narayana polynomials 9362: 9303: 9276: 9242: 9210: 9184: 9158: 9058: 9017: 8973: 8938: 8903: 8892:Ge Yuan Mi Lu Jie Fa 8711: 8619: 8554: 8506: 8350: 8179: 8092: 8066: 7980: 7969:{\displaystyle 2n+1} 7951: 7931: 7905: 7853: 7821: 7801: 7775: 7755: 7735: 7696: 7660: 7624: 7588: 7552: 7526: 7500: 7470: 7444: 7424: 7404: 7306: 7207: 7125: 7043: 6802: 6671: 6648: 6628: 6605: 6513: 6476: 6465:{\displaystyle (c)b} 6447: 6388: 6368: 6348: 6207: 6177: 6128: 6085: 6040: 5918: 5792: 5707: 5624: 5481: 5436: 5405: 5359: 5257: 5211: 4865: 4716: 4596: 4375: 3682: 3609: 3534: 3466: 3370: 3288: 3105: 3002: 2991:Proof of the formula 2979:{\displaystyle 1213} 2970: 2856: 2830: 2810: 2790: 2770: 2750: 2719: 2408:{\displaystyle n=3:} 2390: 2336:{\displaystyle n=2:} 2318: 2298:{\displaystyle n=1:} 2280: 2260:{\displaystyle n=0:} 2242: 1522:by combinatorialist 1433: 1406: 1395:{\displaystyle 2k+1} 1377: 1305: 1120: 1046: 952: 827: 700: 692:recurrence relations 596: 465: 432: 337: 104: 12343:Kaprekar's constant 11863:Colossally abundant 11750:Catalan pseudoprime 11650:Schröder–Hipparchus 11429:Centered octahedral 11305:Centered heptagonal 11295:Centered pentagonal 11285:Centered triangular 10885:and related numbers 10647:1988ttom.book.....G 10622:The Book of Numbers 10381:Larcombe, Peter J. 10173:10.3390/math5030040 9989:Fuss–Catalan number 9199:{\displaystyle m=n} 9173:{\displaystyle m=1} 8336:. For example, for 8165:. For example, for 8081:{\displaystyle n+1} 7920:{\displaystyle n+1} 7790:{\displaystyle n+1} 7541:{\displaystyle m-n} 7515:{\displaystyle m+n} 7485:{\displaystyle m-n} 5496:{\displaystyle LXF} 3279:generating function 3097:recurrence relation 3078:generating function 2845:{\displaystyle n=4} 2706:hook-length formula 2235: 2085:permutation pattern 1594:. A Dyck word is a 1244: 1165: 12761:Mathematics portal 12703:Aronson's sequence 12449:Smarandache–Wellin 12206:-dependent numbers 11913:Primitive abundant 11800:Strong pseudoprime 11790:Perrin pseudoprime 11770:Fermat pseudoprime 11710:Wolstenholme prime 11534:Squared triangular 11320:Centered decagonal 11315:Centered nonagonal 11310:Centered octagonal 11300:Centered hexagonal 10797:Weisstein, Eric W. 10239:(1758/59) 203–209. 9974:Catalan's triangle 9969:Binomial transform 9950:Mathematics portal 9922: 9917: 9864: 9648: 9447: 9316: 9289: 9248: 9228: 9196: 9170: 9129: 9030: 8991: 8959: 8924: 8854: 8823: 8811: 8694: 8682: 8602: 8590: 8537: 8525: 8462: 8450: 8291: 8279: 8098: 8078: 8052: 8051: 7966: 7937: 7917: 7891: 7890: 7839: 7807: 7787: 7761: 7741: 7718: 7682: 7646: 7610: 7574: 7538: 7512: 7482: 7456: 7430: 7410: 7367: 7289: 7190: 7108: 7019: 6782: 6654: 6634: 6617:{\displaystyle c)} 6614: 6588: 6496: 6462: 6433: 6432: 6374: 6354: 6315: 6190: 6163: 6098: 6069:gives the result. 6059: 6023: 5898: 5773: 5772: 5689: 5493: 5467: 5418: 5391: 5390: 5323: 5322: 5243: 5242: 5207:. Since there are 5137: 5113: 5053: 4997: 4845: 4628: 4626: 4565: 4512: 4361: 4359: 3659: 3640: 3588: 3520: 3449:quadratic equation 3419: 3350: 3213: 3063: 2976: 2940: 2842: 2816: 2796: 2776: 2756: 2732: 2405: 2333: 2295: 2257: 2233: 2207: 2143:never exceeds the 1939: 1882: 1871: 1781: 1765: 1730:. It follows that 1683:applications of a 1570: 1524:Richard P. Stanley 1496: 1419: 1392: 1359: 1288: 1227: 1151: 1058:{\displaystyle n!} 1055: 1013: 935: 807: 670: 557: 555: 526: 503: 448: 418: 273: 74:, often involving 52: 21:Catalan's constant 12782:Integer sequences 12769: 12768: 12747: 12746: 12716: 12715: 12680: 12679: 12644: 12643: 12608: 12607: 12568: 12567: 12564: 12563: 12383: 12382: 12193: 12192: 12082: 12081: 12078: 12077: 12024:Aliquot sequences 11835:Divisor functions 11808: 11807: 11780:Lucas pseudoprime 11760:Euler pseudoprime 11745:Carmichael number 11723: 11722: 11678: 11677: 11555: 11554: 11551: 11550: 11547: 11546: 11508: 11507: 11396: 11395: 11353:Square triangular 11245: 11244: 11192: 11191: 11144: 11143: 11078: 11077: 11030: 11029: 10968: 10967: 10729:978-0-521-56069-6 10676:978-0-19-533454-8 10608:978-1-107-42774-7 10501:(5): 111808, 11, 10113:(5): 111808, 11, 9913: 9863: 9685: 9647: 9445: 9365: 9251:{\displaystyle 4} 9127: 8101:{\displaystyle n} 8030: 8003: 7940:{\displaystyle n} 7882: 7810:{\displaystyle n} 7764:{\displaystyle n} 7744:{\displaystyle n} 7433:{\displaystyle n} 7413:{\displaystyle m} 7359: 7338: 7281: 7245: 7182: 7100: 6758: 6657:{\displaystyle )} 6637:{\displaystyle (} 6424: 6377:{\displaystyle )} 6357:{\displaystyle (} 6304: 6230: 5948: 5738: 5382: 5311: 5290: 5234: 5143:: given any path 4986: 4965: 4938: 4900: 4837: 4799: 4761: 4619: 4490: 4469: 4427: 4416: 4329: 4308: 4250: 4153: 4035: 3894: 3766: 3709: 3625: 3586: 3575: 3518: 3507: 3457:quadratic formula 3202: 3128: 3055: 3034: 2819:{\displaystyle 1} 2799:{\displaystyle 1} 2779:{\displaystyle 0} 2759:{\displaystyle 1} 2685:is the number of 2671: 2670: 2114:is the number of 1952:is the number of 1583:is the number of 1488: 1351: 1276: 1215: 1194: 1193: 1149: 1007: 1004: 924: 902: 850: 796: 723: 658: 631: 548: 525: 496: 410: 372: 291:= 0, 1, 2, 3, ... 262: 256: 214: 157: 136: 72:counting problems 12804: 12759: 12722: 12721: 12691:Natural language 12686: 12685: 12650: 12649: 12618:Generated via a 12614: 12613: 12574: 12573: 12479:Digit-reassembly 12444:Self-descriptive 12248: 12247: 12213: 12212: 12199: 12198: 12150:Lucas–Carmichael 12140:Harmonic divisor 12088: 12087: 12014:Sparsely totient 11989:Highly cototient 11898:Multiply perfect 11888:Highly composite 11831: 11830: 11814: 11813: 11729: 11728: 11684: 11683: 11665:Telephone number 11561: 11560: 11519: 11518: 11500:Square pyramidal 11482:Stella octangula 11407: 11406: 11273: 11272: 11264: 11263: 11256:Figurate numbers 11251: 11250: 11198: 11197: 11150: 11149: 11084: 11083: 11036: 11035: 10974: 10973: 10878: 10877: 10862: 10855: 10848: 10839: 10838: 10829: 10810: 10809: 10800:"Catalan Number" 10791: 10790: 10771: 10770: 10753: 10752: 10740: 10708: 10696: 10679: 10659: 10639:253–266 (Ch. 20) 10587: 10586: 10576: 10566: 10542: 10536: 10535: 10510: 10490: 10484: 10463: 10457: 10456: 10454: 10442: 10436: 10435: 10433: 10421: 10415: 10414: 10412: 10411: 10402:. Archived from 10396: 10390: 10389: 10387: 10378: 10372: 10371: 10369: 10357: 10351: 10350: 10332: 10323: 10317: 10316: 10297: 10291: 10290: 10289: 10261: 10255: 10246: 10240: 10230: 10224: 10223: 10213: 10204: 10198: 10195: 10189: 10184: 10178: 10176: 10175: 10155: 10149: 10147: 10122: 10102: 10096: 10095: 10084:10.2307/27646275 10069: 10060: 9952: 9947: 9946: 9931: 9929: 9928: 9923: 9921: 9920: 9914: 9911: 9901: 9900: 9896: 9865: 9862: 9831: 9796: 9766: 9759: 9693: 9686: 9683: 9673: 9672: 9668: 9649: 9646: 9615: 9586: 9565: 9552: 9498: 9484: 9483: 9482: 9481: 9464: 9463: 9462: 9461: 9446: 9444: 9437: 9436: 9418: 9417: 9407: 9400: 9399: 9381: 9380: 9354: 9344: 9325: 9323: 9322: 9317: 9315: 9314: 9298: 9296: 9295: 9290: 9288: 9287: 9257: 9255: 9254: 9249: 9237: 9235: 9234: 9229: 9205: 9203: 9202: 9197: 9179: 9177: 9176: 9171: 9138: 9136: 9135: 9130: 9128: 9126: 9094: 9062: 9050: 9046: 9039: 9037: 9036: 9031: 9029: 9028: 9013:. Specifically, 9000: 8998: 8997: 8992: 8968: 8966: 8965: 8960: 8933: 8931: 8930: 8925: 8832: 8830: 8829: 8824: 8816: 8815: 8703: 8701: 8700: 8695: 8687: 8686: 8611: 8609: 8608: 8603: 8595: 8594: 8546: 8544: 8543: 8538: 8530: 8529: 8498: 8492:has determinant 8491: 8487: 8471: 8469: 8468: 8463: 8455: 8454: 8342: 8335: 8331: 8315: 8300: 8298: 8297: 8292: 8284: 8283: 8171: 8164: 8156: 8140: 8125: 8107: 8105: 8104: 8099: 8087: 8085: 8084: 8079: 8061: 8059: 8058: 8053: 8050: 8049: 8037: 8036: 8035: 8026: 8011: 8004: 8002: 7985: 7975: 7973: 7972: 7967: 7946: 7944: 7943: 7938: 7926: 7924: 7923: 7918: 7900: 7898: 7897: 7892: 7889: 7888: 7887: 7878: 7863: 7848: 7846: 7845: 7840: 7816: 7814: 7813: 7808: 7796: 7794: 7793: 7788: 7770: 7768: 7767: 7762: 7750: 7748: 7747: 7742: 7727: 7725: 7724: 7719: 7717: 7716: 7691: 7689: 7688: 7683: 7681: 7680: 7655: 7653: 7652: 7647: 7645: 7644: 7619: 7617: 7616: 7611: 7609: 7608: 7583: 7581: 7580: 7575: 7573: 7572: 7547: 7545: 7544: 7539: 7521: 7519: 7518: 7513: 7491: 7489: 7488: 7483: 7466:, has precisely 7465: 7463: 7462: 7457: 7439: 7437: 7436: 7431: 7419: 7417: 7416: 7411: 7376: 7374: 7373: 7368: 7366: 7365: 7364: 7355: 7346: 7339: 7337: 7323: 7318: 7317: 7298: 7296: 7295: 7290: 7288: 7287: 7286: 7277: 7262: 7252: 7251: 7250: 7241: 7232: 7219: 7218: 7199: 7197: 7196: 7191: 7189: 7188: 7187: 7178: 7163: 7153: 7152: 7137: 7136: 7117: 7115: 7114: 7109: 7107: 7106: 7105: 7096: 7081: 7071: 7070: 7058: 7057: 7035: 7028: 7026: 7025: 7020: 7015: 7014: 6996: 6995: 6983: 6982: 6966: 6961: 6943: 6942: 6926: 6925: 6915: 6910: 6892: 6891: 6876: 6875: 6865: 6860: 6839: 6838: 6820: 6819: 6791: 6789: 6788: 6783: 6781: 6780: 6765: 6764: 6763: 6754: 6739: 6731: 6726: 6708: 6707: 6689: 6688: 6663: 6661: 6660: 6655: 6643: 6641: 6640: 6635: 6623: 6621: 6620: 6615: 6597: 6595: 6594: 6589: 6584: 6583: 6568: 6567: 6557: 6552: 6531: 6530: 6505: 6503: 6502: 6497: 6489: 6471: 6469: 6468: 6463: 6442: 6440: 6439: 6434: 6431: 6430: 6429: 6420: 6411: 6401: 6400: 6383: 6381: 6380: 6375: 6363: 6361: 6360: 6355: 6343: 6339: 6332: 6324: 6322: 6321: 6316: 6305: 6302: 6299: 6298: 6282: 6281: 6271: 6266: 6248: 6247: 6231: 6228: 6219: 6218: 6199: 6197: 6196: 6191: 6189: 6188: 6172: 6170: 6169: 6164: 6162: 6161: 6149: 6148: 6123: 6119: 6115: 6111: 6107: 6105: 6104: 6099: 6097: 6096: 6068: 6066: 6065: 6060: 6052: 6051: 6032: 6030: 6029: 6024: 5962: 5961: 5949: 5947: 5939: 5922: 5907: 5905: 5904: 5899: 5867: 5866: 5782: 5780: 5779: 5774: 5768: 5767: 5755: 5754: 5739: 5737: 5726: 5712: 5698: 5696: 5695: 5690: 5688: 5687: 5654: 5653: 5613: 5609: 5602: 5585: 5578: 5575:Given a polygon 5571: 5555: 5547: 5540: 5537:Given a polygon 5533: 5521: 5502: 5500: 5499: 5494: 5476: 5474: 5473: 5468: 5457: 5456: 5431: 5427: 5425: 5424: 5419: 5417: 5416: 5400: 5398: 5397: 5392: 5389: 5388: 5387: 5378: 5369: 5351: 5341: 5332: 5330: 5329: 5324: 5318: 5317: 5316: 5307: 5298: 5291: 5289: 5275: 5270: 5269: 5252: 5250: 5249: 5244: 5241: 5240: 5239: 5230: 5221: 5206: 5202: 5191: 5184: 5177: 5163:horizontal step 5158: 5154: 5150: 5146: 5126: 5122: 5118: 5103: 5095: 5091: 5084: 5069: 5043: 5032: 5017: 5013: 5006: 5004: 5003: 4998: 4993: 4992: 4991: 4982: 4973: 4966: 4964: 4950: 4945: 4944: 4943: 4937: 4926: 4917: 4907: 4906: 4905: 4896: 4887: 4877: 4876: 4854: 4852: 4851: 4846: 4844: 4843: 4842: 4836: 4825: 4816: 4806: 4805: 4804: 4798: 4787: 4778: 4768: 4767: 4766: 4760: 4749: 4725: 4705: 4693: 4681: 4669: 4662: 4655: 4637: 4635: 4634: 4629: 4627: 4625: 4624: 4615: 4606: 4591: 4584: 4580: 4576: 4562: 4550: 4521: 4519: 4518: 4513: 4507: 4506: 4497: 4496: 4495: 4486: 4477: 4470: 4468: 4454: 4451: 4446: 4428: 4426: 4418: 4417: 4403: 4394: 4370: 4368: 4367: 4362: 4360: 4352: 4351: 4336: 4335: 4334: 4325: 4316: 4309: 4307: 4293: 4290: 4285: 4267: 4266: 4251: 4249: 4223: 4203: 4200: 4195: 4174: 4170: 4169: 4154: 4152: 4132: 4107: 4106: 4090: 4087: 4082: 4064: 4063: 4036: 4034: 4015: 4014: 3998: 3973: 3972: 3953: 3950: 3945: 3921: 3917: 3916: 3895: 3893: 3886: 3885: 3875: 3850: 3849: 3824: 3821: 3816: 3795: 3794: 3773: 3772: 3771: 3762: 3758: 3748: 3740: 3735: 3710: 3696: 3668: 3666: 3665: 3660: 3639: 3621: 3620: 3597: 3595: 3594: 3589: 3587: 3585: 3577: 3576: 3562: 3553: 3529: 3527: 3526: 3521: 3519: 3517: 3509: 3508: 3494: 3485: 3454: 3446: 3428: 3426: 3425: 3420: 3415: 3414: 3359: 3357: 3356: 3351: 3346: 3345: 3336: 3335: 3325: 3320: 3273: 3264: 3252: 3229: 3222: 3220: 3219: 3214: 3203: 3200: 3197: 3196: 3180: 3179: 3169: 3164: 3146: 3145: 3129: 3126: 3117: 3116: 3082:bijective proofs 3072: 3070: 3069: 3064: 3062: 3061: 3060: 3051: 3042: 3035: 3033: 3019: 3014: 3013: 2985: 2983: 2982: 2977: 2961: 2957: 2953: 2949: 2947: 2946: 2941: 2851: 2849: 2848: 2843: 2825: 2823: 2822: 2817: 2805: 2803: 2802: 2797: 2785: 2783: 2782: 2777: 2765: 2763: 2762: 2757: 2745: 2741: 2739: 2738: 2733: 2731: 2730: 2703: 2699: 2692: 2684: 2663: 2660: 2657: 2654: 2650: 2646: 2643: 2640: 2637: 2633: 2629: 2626: 2622: 2618: 2615: 2611: 2605: 2602: 2598: 2595: 2592: 2589: 2585: 2582: 2579: 2576: 2573: 2570: 2566: 2563: 2560: 2557: 2553: 2550: 2547: 2544: 2541: 2538: 2535: 2532: 2529: 2526: 2523: 2518: 2515: 2512: 2509: 2506: 2503: 2500: 2497: 2494: 2491: 2488: 2485: 2482: 2479: 2476: 2473: 2470: 2467: 2464: 2461: 2458: 2455: 2452: 2449: 2446: 2443: 2440: 2437: 2434: 2431: 2428: 2425: 2422: 2419: 2414: 2412: 2411: 2406: 2378: 2375: 2371: 2365: 2362: 2359: 2356: 2353: 2350: 2347: 2342: 2340: 2339: 2334: 2304: 2302: 2301: 2296: 2266: 2264: 2263: 2258: 2236: 2234:Mountain Ranges 2232: 2227: 2223: 2219: 2197: 2190: 2186: 2182: 2169: 2161: 2146: 2142: 2125: 2113: 2100: 2093: 2082: 2074: 2061: 2057: 2027: 2023: 2019: 2015: 2011: 2001: 1990: 1971: 1968:. A permutation 1967: 1951: 1929: 1922: 1911: 1895: 1862: 1850: 1836: 1819: 1804: 1793: 1755: 1751: 1740: 1729: 1710:full binary tree 1697: 1682: 1671: 1664: 1644: 1640: 1605: 1601: 1593: 1582: 1560: 1556: 1545: 1535: 1505: 1503: 1502: 1497: 1489: 1487: 1486: 1468: 1467: 1458: 1455: 1450: 1428: 1426: 1425: 1420: 1418: 1417: 1401: 1399: 1398: 1393: 1368: 1366: 1365: 1360: 1352: 1350: 1349: 1340: 1339: 1330: 1327: 1322: 1297: 1295: 1294: 1289: 1277: 1275: 1274: 1259: 1257: 1256: 1243: 1238: 1226: 1225: 1216: 1208: 1195: 1189: 1178: 1177: 1175: 1174: 1164: 1159: 1150: 1148: 1137: 1132: 1131: 1109: 1099: 1089: 1082: 1064: 1062: 1061: 1056: 1030: 1026: 1022: 1020: 1019: 1014: 1008: 1006: 1005: 1000: 998: 997: 993: 979: 978: 969: 964: 963: 944: 942: 941: 936: 925: 922: 919: 918: 903: 901: 890: 867: 862: 861: 851: 848: 839: 838: 816: 814: 813: 808: 797: 794: 791: 790: 775: 774: 758: 753: 735: 734: 724: 721: 712: 711: 679: 677: 676: 671: 665: 664: 663: 654: 639: 632: 630: 613: 608: 607: 577: 566: 564: 563: 558: 556: 554: 553: 544: 535: 527: 524: 510: 504: 502: 501: 495: 484: 475: 457: 455: 454: 449: 427: 425: 424: 419: 417: 416: 415: 409: 398: 389: 379: 378: 377: 368: 359: 349: 348: 329: 305: 299: 292: 282: 280: 279: 274: 263: 260: 257: 252: 241: 238: 233: 215: 213: 186: 169: 164: 163: 162: 153: 144: 137: 135: 121: 116: 115: 92: 39: 12812: 12811: 12807: 12806: 12805: 12803: 12802: 12801: 12772: 12771: 12770: 12765: 12743: 12739:Strobogrammatic 12730: 12712: 12694: 12676: 12658: 12640: 12622: 12604: 12581: 12560: 12544: 12503:Divisor-related 12498: 12458: 12409: 12379: 12316: 12300: 12279: 12246: 12219: 12207: 12189: 12101: 12100:related numbers 12074: 12051: 12018: 12009:Perfect totient 11975: 11952: 11883:Highly abundant 11825: 11804: 11736: 11719: 11691: 11674: 11660:Stirling second 11566: 11543: 11504: 11486: 11443: 11392: 11329: 11290:Centered square 11258: 11241: 11203: 11188: 11155: 11140: 11092: 11091:defined numbers 11074: 11041: 11026: 10997:Double Mersenne 10983: 10964: 10886: 10872: 10870:natural numbers 10866: 10815:Catalan numbers 10788: 10778: 10750: 10730: 10694: 10677: 10657: 10629:Gardner, Martin 10600:Catalan numbers 10595: 10590: 10551:Adv. Appl. Math 10543: 10539: 10491: 10487: 10464: 10460: 10443: 10439: 10422: 10418: 10409: 10407: 10398: 10397: 10393: 10385: 10379: 10375: 10358: 10354: 10330: 10324: 10320: 10298: 10294: 10262: 10258: 10247: 10243: 10231: 10227: 10211: 10205: 10201: 10196: 10192: 10185: 10181: 10156: 10152: 10103: 10099: 10067: 10061: 10057: 10053: 10048: 10019:Schröder number 10009:Narayana number 9984:Delannoy number 9948: 9941: 9938: 9916: 9915: 9910: 9905: 9892: 9870: 9866: 9827: 9792: 9767: 9755: 9694: 9691: 9688: 9687: 9682: 9677: 9664: 9654: 9650: 9611: 9582: 9566: 9548: 9499: 9496: 9489: 9488: 9477: 9473: 9472: 9468: 9457: 9453: 9452: 9448: 9432: 9428: 9413: 9409: 9408: 9395: 9391: 9376: 9372: 9371: 9369: 9363: 9360: 9359: 9346: 9342: 9339: 9310: 9306: 9304: 9301: 9300: 9283: 9279: 9277: 9274: 9273: 9243: 9240: 9239: 9211: 9208: 9207: 9185: 9182: 9181: 9159: 9156: 9155: 9095: 9063: 9061: 9059: 9056: 9055: 9048: 9041: 9024: 9020: 9018: 9015: 9014: 9007: 9005:Generalizations 8974: 8971: 8970: 8939: 8936: 8935: 8904: 8901: 8900: 8866:Towers of Hanoi 8842: 8810: 8809: 8804: 8799: 8794: 8788: 8787: 8782: 8777: 8772: 8766: 8765: 8760: 8755: 8750: 8744: 8743: 8738: 8733: 8728: 8718: 8717: 8712: 8709: 8708: 8681: 8680: 8675: 8670: 8664: 8663: 8658: 8653: 8647: 8646: 8641: 8636: 8626: 8625: 8620: 8617: 8616: 8589: 8588: 8583: 8577: 8576: 8571: 8561: 8560: 8555: 8552: 8551: 8524: 8523: 8513: 8512: 8507: 8504: 8503: 8493: 8489: 8479: 8449: 8448: 8443: 8438: 8433: 8427: 8426: 8421: 8416: 8411: 8405: 8404: 8399: 8394: 8389: 8383: 8382: 8377: 8372: 8367: 8357: 8356: 8351: 8348: 8347: 8337: 8333: 8330: 8317: 8305: 8278: 8277: 8272: 8267: 8262: 8256: 8255: 8250: 8245: 8240: 8234: 8233: 8228: 8223: 8218: 8212: 8211: 8206: 8201: 8196: 8186: 8185: 8180: 8177: 8176: 8166: 8162: 8155: 8142: 8130: 8117: 8114: 8093: 8090: 8089: 8067: 8064: 8063: 8045: 8041: 8031: 8013: 8007: 8006: 8005: 7989: 7984: 7981: 7978: 7977: 7952: 7949: 7948: 7932: 7929: 7928: 7906: 7903: 7902: 7883: 7865: 7859: 7858: 7857: 7854: 7851: 7850: 7822: 7819: 7818: 7802: 7799: 7798: 7776: 7773: 7772: 7756: 7753: 7752: 7736: 7733: 7732: 7700: 7699: 7697: 7694: 7693: 7664: 7663: 7661: 7658: 7657: 7628: 7627: 7625: 7622: 7621: 7592: 7591: 7589: 7586: 7585: 7556: 7555: 7553: 7550: 7549: 7527: 7524: 7523: 7501: 7498: 7497: 7494:circular shifts 7471: 7468: 7467: 7445: 7442: 7441: 7425: 7422: 7421: 7405: 7402: 7401: 7383: 7360: 7348: 7342: 7341: 7340: 7327: 7322: 7313: 7309: 7307: 7304: 7303: 7282: 7264: 7258: 7257: 7256: 7246: 7234: 7228: 7227: 7226: 7214: 7210: 7208: 7205: 7204: 7183: 7165: 7159: 7158: 7157: 7148: 7144: 7132: 7128: 7126: 7123: 7122: 7101: 7083: 7077: 7076: 7075: 7066: 7062: 7053: 7049: 7044: 7041: 7040: 7033: 7004: 7000: 6991: 6987: 6978: 6974: 6962: 6951: 6932: 6928: 6921: 6917: 6911: 6900: 6881: 6877: 6871: 6867: 6861: 6850: 6828: 6824: 6809: 6805: 6803: 6800: 6799: 6770: 6766: 6759: 6741: 6735: 6734: 6733: 6727: 6716: 6697: 6693: 6678: 6674: 6672: 6669: 6668: 6649: 6646: 6645: 6629: 6626: 6625: 6606: 6603: 6602: 6573: 6569: 6563: 6559: 6553: 6542: 6520: 6516: 6514: 6511: 6510: 6482: 6477: 6474: 6473: 6448: 6445: 6444: 6425: 6413: 6407: 6406: 6405: 6396: 6392: 6389: 6386: 6385: 6369: 6366: 6365: 6349: 6346: 6345: 6341: 6334: 6330: 6301: 6288: 6284: 6277: 6273: 6267: 6256: 6237: 6233: 6227: 6214: 6210: 6208: 6205: 6204: 6184: 6180: 6178: 6175: 6174: 6157: 6153: 6144: 6140: 6129: 6126: 6125: 6121: 6117: 6113: 6109: 6092: 6088: 6086: 6083: 6082: 6075: 6047: 6043: 6041: 6038: 6037: 5957: 5953: 5940: 5923: 5921: 5919: 5916: 5915: 5862: 5858: 5793: 5790: 5789: 5763: 5759: 5744: 5740: 5727: 5713: 5711: 5708: 5705: 5704: 5677: 5673: 5649: 5645: 5625: 5622: 5621: 5611: 5607: 5601: 5587: 5580: 5576: 5570: 5557: 5549: 5542: 5538: 5532: 5523: 5520: 5512: 5509: 5482: 5479: 5478: 5452: 5448: 5437: 5434: 5433: 5429: 5412: 5408: 5406: 5403: 5402: 5383: 5371: 5365: 5364: 5363: 5360: 5357: 5356: 5349: 5343: 5336: 5312: 5300: 5294: 5293: 5292: 5279: 5274: 5265: 5261: 5258: 5255: 5254: 5235: 5223: 5217: 5216: 5215: 5212: 5209: 5208: 5204: 5197: 5186: 5179: 5175: 5156: 5152: 5148: 5144: 5124: 5120: 5116: 5101: 5093: 5089: 5082: 5067: 5042: 5034: 5027: 5024: 5015: 5011: 4987: 4975: 4969: 4968: 4967: 4954: 4949: 4939: 4927: 4919: 4913: 4912: 4911: 4901: 4889: 4883: 4882: 4881: 4872: 4868: 4866: 4863: 4862: 4838: 4826: 4818: 4812: 4811: 4810: 4800: 4788: 4780: 4774: 4773: 4772: 4762: 4750: 4727: 4721: 4720: 4719: 4717: 4714: 4713: 4695: 4683: 4671: 4664: 4657: 4650: 4620: 4608: 4602: 4601: 4599: 4597: 4594: 4593: 4586: 4582: 4578: 4568: 4552: 4540: 4533: 4527: 4502: 4498: 4491: 4479: 4473: 4472: 4471: 4458: 4453: 4447: 4436: 4419: 4402: 4395: 4393: 4376: 4373: 4372: 4358: 4357: 4341: 4337: 4330: 4318: 4312: 4311: 4310: 4297: 4292: 4286: 4275: 4256: 4252: 4224: 4204: 4202: 4196: 4185: 4172: 4171: 4159: 4155: 4133: 4096: 4092: 4091: 4089: 4083: 4072: 4053: 4049: 4004: 4000: 3999: 3968: 3964: 3954: 3952: 3946: 3935: 3919: 3918: 3912: 3908: 3881: 3877: 3876: 3839: 3835: 3825: 3823: 3817: 3806: 3790: 3786: 3767: 3754: 3750: 3744: 3743: 3742: 3736: 3725: 3711: 3695: 3685: 3683: 3680: 3679: 3675:binomial series 3629: 3616: 3612: 3610: 3607: 3606: 3578: 3561: 3554: 3552: 3535: 3532: 3531: 3530: or  3510: 3493: 3486: 3484: 3467: 3464: 3463: 3452: 3437: 3410: 3406: 3371: 3368: 3367: 3341: 3337: 3331: 3327: 3321: 3310: 3289: 3286: 3285: 3272: 3266: 3263: 3257: 3251: 3244: 3234: 3227: 3199: 3186: 3182: 3175: 3171: 3165: 3154: 3135: 3131: 3125: 3112: 3108: 3106: 3103: 3102: 3090: 3056: 3044: 3038: 3037: 3036: 3023: 3018: 3009: 3005: 3003: 3000: 2999: 2993: 2971: 2968: 2967: 2959: 2955: 2951: 2857: 2854: 2853: 2831: 2828: 2827: 2811: 2808: 2807: 2791: 2788: 2787: 2771: 2768: 2767: 2751: 2748: 2747: 2743: 2726: 2722: 2720: 2717: 2716: 2713: 2701: 2694: 2690: 2683: 2675: 2672: 2661: 2658: 2655: 2652: 2648: 2644: 2641: 2638: 2635: 2631: 2627: 2624: 2620: 2616: 2613: 2609: 2607: 2603: 2600: 2596: 2593: 2590: 2587: 2583: 2580: 2577: 2574: 2571: 2568: 2564: 2561: 2558: 2555: 2551: 2548: 2545: 2542: 2539: 2536: 2533: 2530: 2527: 2524: 2521: 2520: 2516: 2513: 2510: 2507: 2504: 2501: 2498: 2495: 2492: 2489: 2486: 2483: 2480: 2477: 2474: 2471: 2468: 2465: 2462: 2459: 2456: 2453: 2450: 2447: 2444: 2441: 2438: 2435: 2432: 2429: 2426: 2423: 2420: 2417: 2391: 2388: 2387: 2376: 2373: 2369: 2367: 2363: 2360: 2357: 2354: 2351: 2348: 2345: 2319: 2316: 2315: 2281: 2278: 2277: 2243: 2240: 2239: 2225: 2221: 2218: 2210: 2192: 2188: 2184: 2181: 2173: 2163: 2160: 2152: 2144: 2141: 2133: 2119: 2112: 2104: 2095: 2088: 2083:that avoid the 2076: 2073: 2065: 2059: 2029: 2025: 2021: 2017: 2013: 2003: 1992: 1977: 1969: 1961: 1950: 1942: 1924: 1921: 1913: 1909: 1890: 1857: 1842: 1835: 1827: 1818: 1810: 1809:. For example, 1799: 1792: 1784: 1778: 1756:internal nodes: 1753: 1746: 1739: 1731: 1713: 1705: 1704: 1692: 1685:binary operator 1680: 1666: 1663: 1655: 1652: 1651: 1642: 1639: 1631: 1623: 1622: 1618: 1617: 1613: 1612: 1603: 1599: 1588: 1581: 1573: 1561:interpreted as 1558: 1554: 1543: 1537: 1533: 1527: 1512: 1473: 1469: 1463: 1459: 1457: 1451: 1440: 1434: 1431: 1430: 1413: 1409: 1407: 1404: 1403: 1378: 1375: 1374: 1345: 1341: 1335: 1331: 1329: 1323: 1312: 1306: 1303: 1302: 1270: 1266: 1258: 1249: 1245: 1239: 1231: 1221: 1217: 1207: 1179: 1176: 1170: 1166: 1160: 1155: 1141: 1136: 1127: 1123: 1121: 1118: 1117: 1107: 1101: 1097: 1091: 1084: 1081: 1073: 1047: 1044: 1043: 1028: 1024: 999: 989: 985: 981: 980: 974: 970: 968: 959: 955: 953: 950: 949: 921: 908: 904: 891: 868: 866: 857: 853: 847: 834: 830: 828: 825: 824: 793: 780: 776: 764: 760: 754: 743: 730: 726: 720: 707: 703: 701: 698: 697: 659: 641: 635: 634: 633: 617: 612: 603: 599: 597: 594: 593: 576: 568: 549: 537: 531: 530: 528: 514: 508: 497: 485: 477: 471: 470: 468: 466: 463: 462: 433: 430: 429: 411: 399: 391: 385: 384: 383: 373: 361: 355: 354: 353: 344: 340: 338: 335: 334: 328: 320: 317: 301: 297: 287: 259: 242: 240: 234: 223: 187: 170: 168: 158: 146: 140: 139: 138: 125: 120: 111: 107: 105: 102: 101: 90: 68:natural numbers 60:Catalan numbers 37: 33: 24: 17: 12: 11: 5: 12810: 12800: 12799: 12794: 12789: 12784: 12767: 12766: 12764: 12763: 12752: 12749: 12748: 12745: 12744: 12742: 12741: 12735: 12732: 12731: 12718: 12717: 12714: 12713: 12711: 12710: 12705: 12699: 12696: 12695: 12682: 12681: 12678: 12677: 12675: 12674: 12672:Sorting number 12669: 12667:Pancake number 12663: 12660: 12659: 12646: 12645: 12642: 12641: 12639: 12638: 12633: 12627: 12624: 12623: 12610: 12609: 12606: 12605: 12603: 12602: 12597: 12592: 12586: 12583: 12582: 12579:Binary numbers 12570: 12569: 12566: 12565: 12562: 12561: 12559: 12558: 12552: 12550: 12546: 12545: 12543: 12542: 12537: 12532: 12527: 12522: 12517: 12512: 12506: 12504: 12500: 12499: 12497: 12496: 12491: 12486: 12481: 12476: 12470: 12468: 12460: 12459: 12457: 12456: 12451: 12446: 12441: 12436: 12431: 12426: 12420: 12418: 12411: 12410: 12408: 12407: 12406: 12405: 12394: 12392: 12389:P-adic numbers 12385: 12384: 12381: 12380: 12378: 12377: 12376: 12375: 12365: 12360: 12355: 12350: 12345: 12340: 12335: 12330: 12324: 12322: 12318: 12317: 12315: 12314: 12308: 12306: 12305:Coding-related 12302: 12301: 12299: 12298: 12293: 12287: 12285: 12281: 12280: 12278: 12277: 12272: 12267: 12262: 12256: 12254: 12245: 12244: 12243: 12242: 12240:Multiplicative 12237: 12226: 12224: 12209: 12208: 12204:Numeral system 12195: 12194: 12191: 12190: 12188: 12187: 12182: 12177: 12172: 12167: 12162: 12157: 12152: 12147: 12142: 12137: 12132: 12127: 12122: 12117: 12112: 12106: 12103: 12102: 12084: 12083: 12080: 12079: 12076: 12075: 12073: 12072: 12067: 12061: 12059: 12053: 12052: 12050: 12049: 12044: 12039: 12034: 12028: 12026: 12020: 12019: 12017: 12016: 12011: 12006: 12001: 11996: 11994:Highly totient 11991: 11985: 11983: 11977: 11976: 11974: 11973: 11968: 11962: 11960: 11954: 11953: 11951: 11950: 11945: 11940: 11935: 11930: 11925: 11920: 11915: 11910: 11905: 11900: 11895: 11890: 11885: 11880: 11875: 11870: 11865: 11860: 11855: 11850: 11848:Almost perfect 11845: 11839: 11837: 11827: 11826: 11810: 11809: 11806: 11805: 11803: 11802: 11797: 11792: 11787: 11782: 11777: 11772: 11767: 11762: 11757: 11752: 11747: 11741: 11738: 11737: 11725: 11724: 11721: 11720: 11718: 11717: 11712: 11707: 11702: 11696: 11693: 11692: 11680: 11679: 11676: 11675: 11673: 11672: 11667: 11662: 11657: 11655:Stirling first 11652: 11647: 11642: 11637: 11632: 11627: 11622: 11617: 11612: 11607: 11602: 11597: 11592: 11587: 11582: 11577: 11571: 11568: 11567: 11557: 11556: 11553: 11552: 11549: 11548: 11545: 11544: 11542: 11541: 11536: 11531: 11525: 11523: 11516: 11510: 11509: 11506: 11505: 11503: 11502: 11496: 11494: 11488: 11487: 11485: 11484: 11479: 11474: 11469: 11464: 11459: 11453: 11451: 11445: 11444: 11442: 11441: 11436: 11431: 11426: 11421: 11415: 11413: 11404: 11398: 11397: 11394: 11393: 11391: 11390: 11385: 11380: 11375: 11370: 11365: 11360: 11355: 11350: 11345: 11339: 11337: 11331: 11330: 11328: 11327: 11322: 11317: 11312: 11307: 11302: 11297: 11292: 11287: 11281: 11279: 11270: 11260: 11259: 11247: 11246: 11243: 11242: 11240: 11239: 11234: 11229: 11224: 11219: 11214: 11208: 11205: 11204: 11194: 11193: 11190: 11189: 11187: 11186: 11181: 11176: 11171: 11166: 11160: 11157: 11156: 11146: 11145: 11142: 11141: 11139: 11138: 11133: 11128: 11123: 11118: 11113: 11108: 11103: 11097: 11094: 11093: 11080: 11079: 11076: 11075: 11073: 11072: 11067: 11062: 11057: 11052: 11046: 11043: 11042: 11032: 11031: 11028: 11027: 11025: 11024: 11019: 11014: 11009: 11004: 10999: 10994: 10988: 10985: 10984: 10970: 10969: 10966: 10965: 10963: 10962: 10957: 10952: 10947: 10942: 10937: 10932: 10927: 10922: 10917: 10912: 10907: 10902: 10897: 10891: 10888: 10887: 10874: 10873: 10865: 10864: 10857: 10850: 10842: 10836: 10835: 10834:at Wikiversity 10823: 10818: 10811: 10792: 10777: 10776:External links 10774: 10773: 10772: 10754: 10741: 10728: 10709: 10687: 10680: 10675: 10660: 10655: 10625: 10611: 10594: 10591: 10589: 10588: 10537: 10485: 10458: 10437: 10416: 10391: 10373: 10352: 10318: 10308:(2): 305–313, 10292: 10256: 10241: 10225: 10199: 10190: 10179: 10150: 10097: 10054: 10052: 10049: 10047: 10046: 10041: 10036: 10034:Tamari lattice 10031: 10026: 10021: 10016: 10011: 10006: 10004:Motzkin number 10001: 9996: 9991: 9986: 9981: 9976: 9971: 9966: 9961: 9955: 9954: 9953: 9937: 9934: 9933: 9932: 9919: 9909: 9906: 9904: 9899: 9895: 9891: 9888: 9885: 9882: 9879: 9876: 9873: 9869: 9861: 9858: 9855: 9852: 9849: 9846: 9843: 9840: 9837: 9834: 9830: 9826: 9823: 9820: 9817: 9814: 9811: 9808: 9805: 9802: 9799: 9795: 9791: 9788: 9785: 9782: 9779: 9776: 9773: 9770: 9765: 9762: 9758: 9754: 9751: 9748: 9745: 9742: 9739: 9736: 9733: 9730: 9727: 9724: 9721: 9718: 9715: 9712: 9709: 9706: 9703: 9700: 9697: 9690: 9689: 9681: 9678: 9676: 9671: 9667: 9663: 9660: 9657: 9653: 9645: 9642: 9639: 9636: 9633: 9630: 9627: 9624: 9621: 9618: 9614: 9610: 9607: 9604: 9601: 9598: 9595: 9592: 9589: 9585: 9581: 9578: 9575: 9572: 9569: 9564: 9561: 9558: 9555: 9551: 9547: 9544: 9541: 9538: 9535: 9532: 9529: 9526: 9523: 9520: 9517: 9514: 9511: 9508: 9505: 9502: 9495: 9494: 9492: 9487: 9480: 9476: 9471: 9467: 9460: 9456: 9451: 9443: 9440: 9435: 9431: 9427: 9424: 9421: 9416: 9412: 9406: 9403: 9398: 9394: 9390: 9387: 9384: 9379: 9375: 9368: 9338: 9335: 9313: 9309: 9286: 9282: 9247: 9227: 9224: 9221: 9218: 9215: 9195: 9192: 9189: 9169: 9166: 9163: 9125: 9122: 9119: 9116: 9113: 9110: 9107: 9104: 9101: 9098: 9093: 9090: 9087: 9084: 9081: 9078: 9075: 9072: 9069: 9066: 9027: 9023: 9006: 9003: 8990: 8987: 8984: 8981: 8978: 8958: 8955: 8952: 8949: 8946: 8943: 8923: 8920: 8917: 8914: 8911: 8908: 8858:Leonhard Euler 8841: 8838: 8834: 8833: 8822: 8819: 8814: 8808: 8805: 8803: 8800: 8798: 8795: 8793: 8790: 8789: 8786: 8783: 8781: 8778: 8776: 8773: 8771: 8768: 8767: 8764: 8761: 8759: 8756: 8754: 8751: 8749: 8746: 8745: 8742: 8739: 8737: 8734: 8732: 8729: 8727: 8724: 8723: 8721: 8716: 8705: 8704: 8693: 8690: 8685: 8679: 8676: 8674: 8671: 8669: 8666: 8665: 8662: 8659: 8657: 8654: 8652: 8649: 8648: 8645: 8642: 8640: 8637: 8635: 8632: 8631: 8629: 8624: 8613: 8612: 8601: 8598: 8593: 8587: 8584: 8582: 8579: 8578: 8575: 8572: 8570: 8567: 8566: 8564: 8559: 8548: 8547: 8536: 8533: 8528: 8522: 8519: 8518: 8516: 8511: 8473: 8472: 8461: 8458: 8453: 8447: 8444: 8442: 8439: 8437: 8434: 8432: 8429: 8428: 8425: 8422: 8420: 8417: 8415: 8412: 8410: 8407: 8406: 8403: 8400: 8398: 8395: 8393: 8390: 8388: 8385: 8384: 8381: 8378: 8376: 8373: 8371: 8368: 8366: 8363: 8362: 8360: 8355: 8321: 8302: 8301: 8290: 8287: 8282: 8276: 8273: 8271: 8268: 8266: 8263: 8261: 8258: 8257: 8254: 8251: 8249: 8246: 8244: 8241: 8239: 8236: 8235: 8232: 8229: 8227: 8224: 8222: 8219: 8217: 8214: 8213: 8210: 8207: 8205: 8202: 8200: 8197: 8195: 8192: 8191: 8189: 8184: 8146: 8113: 8110: 8097: 8077: 8074: 8071: 8048: 8044: 8040: 8034: 8029: 8025: 8022: 8019: 8016: 8010: 8001: 7998: 7995: 7992: 7988: 7965: 7962: 7959: 7956: 7936: 7916: 7913: 7910: 7886: 7881: 7877: 7874: 7871: 7868: 7862: 7838: 7835: 7832: 7829: 7826: 7806: 7786: 7783: 7780: 7760: 7740: 7715: 7712: 7709: 7706: 7703: 7679: 7676: 7673: 7670: 7667: 7643: 7640: 7637: 7634: 7631: 7607: 7604: 7601: 7598: 7595: 7571: 7568: 7565: 7562: 7559: 7537: 7534: 7531: 7511: 7508: 7505: 7481: 7478: 7475: 7455: 7452: 7449: 7429: 7409: 7382: 7379: 7378: 7377: 7363: 7358: 7354: 7351: 7345: 7336: 7333: 7330: 7326: 7321: 7316: 7312: 7300: 7299: 7285: 7280: 7276: 7273: 7270: 7267: 7261: 7255: 7249: 7244: 7240: 7237: 7231: 7225: 7222: 7217: 7213: 7201: 7200: 7186: 7181: 7177: 7174: 7171: 7168: 7162: 7156: 7151: 7147: 7143: 7140: 7135: 7131: 7119: 7118: 7104: 7099: 7095: 7092: 7089: 7086: 7080: 7074: 7069: 7065: 7061: 7056: 7052: 7048: 7030: 7029: 7018: 7013: 7010: 7007: 7003: 6999: 6994: 6990: 6986: 6981: 6977: 6973: 6970: 6965: 6960: 6957: 6954: 6950: 6946: 6941: 6938: 6935: 6931: 6924: 6920: 6914: 6909: 6906: 6903: 6899: 6895: 6890: 6887: 6884: 6880: 6874: 6870: 6864: 6859: 6856: 6853: 6849: 6845: 6842: 6837: 6834: 6831: 6827: 6823: 6818: 6815: 6812: 6808: 6793: 6792: 6779: 6776: 6773: 6769: 6762: 6757: 6753: 6750: 6747: 6744: 6738: 6730: 6725: 6722: 6719: 6715: 6711: 6706: 6703: 6700: 6696: 6692: 6687: 6684: 6681: 6677: 6653: 6633: 6613: 6610: 6599: 6598: 6587: 6582: 6579: 6576: 6572: 6566: 6562: 6556: 6551: 6548: 6545: 6541: 6537: 6534: 6529: 6526: 6523: 6519: 6495: 6492: 6488: 6485: 6481: 6461: 6458: 6455: 6452: 6428: 6423: 6419: 6416: 6410: 6404: 6399: 6395: 6373: 6353: 6327: 6326: 6314: 6311: 6308: 6297: 6294: 6291: 6287: 6280: 6276: 6270: 6265: 6262: 6259: 6255: 6251: 6246: 6243: 6240: 6236: 6225: 6222: 6217: 6213: 6187: 6183: 6160: 6156: 6152: 6147: 6143: 6139: 6136: 6133: 6095: 6091: 6074: 6071: 6058: 6055: 6050: 6046: 6034: 6033: 6022: 6019: 6016: 6013: 6010: 6007: 6004: 6001: 5998: 5995: 5992: 5989: 5986: 5983: 5980: 5977: 5974: 5971: 5968: 5965: 5960: 5956: 5952: 5946: 5943: 5938: 5935: 5932: 5929: 5926: 5909: 5908: 5897: 5894: 5891: 5888: 5885: 5882: 5879: 5876: 5873: 5870: 5865: 5861: 5857: 5854: 5851: 5848: 5845: 5842: 5839: 5836: 5833: 5830: 5827: 5824: 5821: 5818: 5815: 5812: 5809: 5806: 5803: 5800: 5797: 5771: 5766: 5762: 5758: 5753: 5750: 5747: 5743: 5736: 5733: 5730: 5725: 5722: 5719: 5716: 5701: 5700: 5686: 5683: 5680: 5676: 5672: 5669: 5666: 5663: 5660: 5657: 5652: 5648: 5644: 5641: 5638: 5635: 5632: 5629: 5596: 5566: 5527: 5516: 5508: 5505: 5492: 5489: 5486: 5466: 5463: 5460: 5455: 5451: 5447: 5444: 5441: 5415: 5411: 5386: 5381: 5377: 5374: 5368: 5347: 5321: 5315: 5310: 5306: 5303: 5297: 5288: 5285: 5282: 5278: 5273: 5268: 5264: 5238: 5233: 5229: 5226: 5220: 5171:the diagonal. 5098: 5097: 5086: 5075: 5038: 5023: 5020: 5008: 5007: 4996: 4990: 4985: 4981: 4978: 4972: 4963: 4960: 4957: 4953: 4948: 4942: 4936: 4933: 4930: 4925: 4922: 4916: 4910: 4904: 4899: 4895: 4892: 4886: 4880: 4875: 4871: 4856: 4855: 4841: 4835: 4832: 4829: 4824: 4821: 4815: 4809: 4803: 4797: 4794: 4791: 4786: 4783: 4777: 4771: 4765: 4759: 4756: 4753: 4748: 4745: 4742: 4739: 4736: 4733: 4730: 4724: 4623: 4618: 4614: 4611: 4605: 4526: 4523: 4511: 4505: 4501: 4494: 4489: 4485: 4482: 4476: 4467: 4464: 4461: 4457: 4450: 4445: 4442: 4439: 4435: 4431: 4425: 4422: 4415: 4412: 4409: 4406: 4401: 4398: 4392: 4389: 4386: 4383: 4380: 4356: 4350: 4347: 4344: 4340: 4333: 4328: 4324: 4321: 4315: 4306: 4303: 4300: 4296: 4289: 4284: 4281: 4278: 4274: 4270: 4265: 4262: 4259: 4255: 4248: 4245: 4242: 4239: 4236: 4233: 4230: 4227: 4222: 4219: 4216: 4213: 4210: 4207: 4199: 4194: 4191: 4188: 4184: 4180: 4177: 4175: 4173: 4168: 4165: 4162: 4158: 4151: 4148: 4145: 4142: 4139: 4136: 4131: 4128: 4125: 4122: 4119: 4116: 4113: 4110: 4105: 4102: 4099: 4095: 4086: 4081: 4078: 4075: 4071: 4067: 4062: 4059: 4056: 4052: 4048: 4045: 4042: 4039: 4033: 4030: 4027: 4024: 4021: 4018: 4013: 4010: 4007: 4003: 3997: 3994: 3991: 3988: 3985: 3982: 3979: 3976: 3971: 3967: 3963: 3960: 3957: 3949: 3944: 3941: 3938: 3934: 3930: 3927: 3924: 3922: 3920: 3915: 3911: 3907: 3904: 3901: 3898: 3892: 3889: 3884: 3880: 3874: 3871: 3868: 3865: 3862: 3859: 3856: 3853: 3848: 3845: 3842: 3838: 3834: 3831: 3828: 3820: 3815: 3812: 3809: 3805: 3801: 3798: 3793: 3789: 3785: 3782: 3779: 3776: 3770: 3765: 3761: 3757: 3753: 3747: 3739: 3734: 3731: 3728: 3724: 3720: 3717: 3714: 3712: 3708: 3705: 3702: 3699: 3694: 3691: 3688: 3687: 3671: 3670: 3658: 3655: 3652: 3649: 3646: 3643: 3638: 3635: 3632: 3628: 3624: 3619: 3615: 3600: 3599: 3584: 3581: 3574: 3571: 3568: 3565: 3560: 3557: 3551: 3548: 3545: 3542: 3539: 3516: 3513: 3506: 3503: 3500: 3497: 3492: 3489: 3483: 3480: 3477: 3474: 3471: 3455:and using the 3430: 3429: 3418: 3413: 3409: 3405: 3402: 3399: 3396: 3393: 3390: 3387: 3384: 3381: 3378: 3375: 3361: 3360: 3349: 3344: 3340: 3334: 3330: 3324: 3319: 3316: 3313: 3309: 3305: 3302: 3299: 3296: 3293: 3270: 3261: 3254: 3253: 3249: 3242: 3224: 3223: 3212: 3209: 3206: 3195: 3192: 3189: 3185: 3178: 3174: 3168: 3163: 3160: 3157: 3153: 3149: 3144: 3141: 3138: 3134: 3123: 3120: 3115: 3111: 3089: 3086: 3074: 3073: 3059: 3054: 3050: 3047: 3041: 3032: 3029: 3026: 3022: 3017: 3012: 3008: 2992: 2989: 2988: 2987: 2975: 2939: 2936: 2933: 2930: 2927: 2924: 2921: 2918: 2915: 2912: 2909: 2906: 2903: 2900: 2897: 2894: 2891: 2888: 2885: 2882: 2879: 2876: 2873: 2870: 2867: 2864: 2861: 2841: 2838: 2835: 2815: 2795: 2775: 2755: 2729: 2725: 2711: 2710: 2709: 2679: 2669: 2668: 2665: 2415: 2404: 2401: 2398: 2395: 2384: 2383: 2380: 2343: 2332: 2329: 2326: 2323: 2312: 2311: 2308: 2305: 2294: 2291: 2288: 2285: 2274: 2273: 2270: 2267: 2256: 2253: 2250: 2247: 2230: 2229: 2224:upstrokes and 2214: 2200: 2199: 2177: 2171: 2156: 2137: 2108: 2102: 2069: 2063: 1974:stack-sortable 1946: 1932: 1931: 1917: 1887:convex polygon 1854: 1853: 1831: 1825: 1814: 1805:vertices. See 1788: 1776: 1758: 1757: 1735: 1702: 1701: 1700: 1699: 1691:problem). For 1659: 1649: 1648: 1647: 1646: 1635: 1620: 1619: 1615: 1614: 1610: 1609: 1608: 1607: 1598:consisting of 1577: 1541: 1531: 1511: 1508: 1495: 1492: 1485: 1482: 1479: 1476: 1472: 1466: 1462: 1454: 1449: 1446: 1443: 1439: 1416: 1412: 1391: 1388: 1385: 1382: 1358: 1355: 1348: 1344: 1338: 1334: 1326: 1321: 1318: 1315: 1311: 1299: 1298: 1287: 1284: 1281: 1273: 1269: 1265: 1262: 1255: 1252: 1248: 1242: 1237: 1234: 1230: 1224: 1220: 1214: 1211: 1206: 1202: 1199: 1192: 1188: 1185: 1182: 1173: 1169: 1163: 1158: 1154: 1147: 1144: 1140: 1135: 1130: 1126: 1105: 1095: 1077: 1054: 1051: 1012: 1003: 996: 992: 988: 984: 977: 973: 967: 962: 958: 946: 945: 934: 931: 928: 917: 914: 911: 907: 900: 897: 894: 889: 886: 883: 880: 877: 874: 871: 865: 860: 856: 845: 842: 837: 833: 818: 817: 806: 803: 800: 789: 786: 783: 779: 773: 770: 767: 763: 757: 752: 749: 746: 742: 738: 733: 729: 718: 715: 710: 706: 681: 680: 669: 662: 657: 653: 650: 647: 644: 638: 629: 626: 623: 620: 616: 611: 606: 602: 572: 552: 547: 543: 540: 534: 523: 520: 517: 513: 507: 500: 494: 491: 488: 483: 480: 474: 459: 458: 447: 443: 440: 437: 414: 408: 405: 402: 397: 394: 388: 382: 376: 371: 367: 364: 358: 352: 347: 343: 324: 316: 313: 312: 311: 284: 283: 272: 269: 266: 255: 251: 248: 245: 237: 232: 229: 226: 222: 218: 212: 209: 205: 202: 199: 196: 193: 190: 185: 182: 179: 176: 173: 167: 161: 156: 152: 149: 143: 134: 131: 128: 124: 119: 114: 110: 35: 15: 9: 6: 4: 3: 2: 12809: 12798: 12795: 12793: 12790: 12788: 12785: 12783: 12780: 12779: 12777: 12762: 12758: 12754: 12753: 12750: 12740: 12737: 12736: 12733: 12728: 12723: 12719: 12709: 12706: 12704: 12701: 12700: 12697: 12692: 12687: 12683: 12673: 12670: 12668: 12665: 12664: 12661: 12656: 12651: 12647: 12637: 12634: 12632: 12629: 12628: 12625: 12621: 12615: 12611: 12601: 12598: 12596: 12593: 12591: 12588: 12587: 12584: 12580: 12575: 12571: 12557: 12554: 12553: 12551: 12547: 12541: 12538: 12536: 12533: 12531: 12530:Polydivisible 12528: 12526: 12523: 12521: 12518: 12516: 12513: 12511: 12508: 12507: 12505: 12501: 12495: 12492: 12490: 12487: 12485: 12482: 12480: 12477: 12475: 12472: 12471: 12469: 12466: 12461: 12455: 12452: 12450: 12447: 12445: 12442: 12440: 12437: 12435: 12432: 12430: 12427: 12425: 12422: 12421: 12419: 12416: 12412: 12404: 12401: 12400: 12399: 12396: 12395: 12393: 12390: 12386: 12374: 12371: 12370: 12369: 12366: 12364: 12361: 12359: 12356: 12354: 12351: 12349: 12346: 12344: 12341: 12339: 12336: 12334: 12331: 12329: 12326: 12325: 12323: 12319: 12313: 12310: 12309: 12307: 12303: 12297: 12294: 12292: 12289: 12288: 12286: 12284:Digit product 12282: 12276: 12273: 12271: 12268: 12266: 12263: 12261: 12258: 12257: 12255: 12253: 12249: 12241: 12238: 12236: 12233: 12232: 12231: 12228: 12227: 12225: 12223: 12218: 12214: 12210: 12205: 12200: 12196: 12186: 12183: 12181: 12178: 12176: 12173: 12171: 12168: 12166: 12163: 12161: 12158: 12156: 12153: 12151: 12148: 12146: 12143: 12141: 12138: 12136: 12133: 12131: 12128: 12126: 12123: 12121: 12120:ErdƑs–Nicolas 12118: 12116: 12113: 12111: 12108: 12107: 12104: 12099: 12095: 12089: 12085: 12071: 12068: 12066: 12063: 12062: 12060: 12058: 12054: 12048: 12045: 12043: 12040: 12038: 12035: 12033: 12030: 12029: 12027: 12025: 12021: 12015: 12012: 12010: 12007: 12005: 12002: 12000: 11997: 11995: 11992: 11990: 11987: 11986: 11984: 11982: 11978: 11972: 11969: 11967: 11964: 11963: 11961: 11959: 11955: 11949: 11946: 11944: 11941: 11939: 11938:Superabundant 11936: 11934: 11931: 11929: 11926: 11924: 11921: 11919: 11916: 11914: 11911: 11909: 11906: 11904: 11901: 11899: 11896: 11894: 11891: 11889: 11886: 11884: 11881: 11879: 11876: 11874: 11871: 11869: 11866: 11864: 11861: 11859: 11856: 11854: 11851: 11849: 11846: 11844: 11841: 11840: 11838: 11836: 11832: 11828: 11824: 11820: 11815: 11811: 11801: 11798: 11796: 11793: 11791: 11788: 11786: 11783: 11781: 11778: 11776: 11773: 11771: 11768: 11766: 11763: 11761: 11758: 11756: 11753: 11751: 11748: 11746: 11743: 11742: 11739: 11735: 11730: 11726: 11716: 11713: 11711: 11708: 11706: 11703: 11701: 11698: 11697: 11694: 11690: 11685: 11681: 11671: 11668: 11666: 11663: 11661: 11658: 11656: 11653: 11651: 11648: 11646: 11643: 11641: 11638: 11636: 11633: 11631: 11628: 11626: 11623: 11621: 11618: 11616: 11613: 11611: 11608: 11606: 11603: 11601: 11598: 11596: 11593: 11591: 11588: 11586: 11583: 11581: 11578: 11576: 11573: 11572: 11569: 11562: 11558: 11540: 11537: 11535: 11532: 11530: 11527: 11526: 11524: 11520: 11517: 11515: 11514:4-dimensional 11511: 11501: 11498: 11497: 11495: 11493: 11489: 11483: 11480: 11478: 11475: 11473: 11470: 11468: 11465: 11463: 11460: 11458: 11455: 11454: 11452: 11450: 11446: 11440: 11437: 11435: 11432: 11430: 11427: 11425: 11424:Centered cube 11422: 11420: 11417: 11416: 11414: 11412: 11408: 11405: 11403: 11402:3-dimensional 11399: 11389: 11386: 11384: 11381: 11379: 11376: 11374: 11371: 11369: 11366: 11364: 11361: 11359: 11356: 11354: 11351: 11349: 11346: 11344: 11341: 11340: 11338: 11336: 11332: 11326: 11323: 11321: 11318: 11316: 11313: 11311: 11308: 11306: 11303: 11301: 11298: 11296: 11293: 11291: 11288: 11286: 11283: 11282: 11280: 11278: 11274: 11271: 11269: 11268:2-dimensional 11265: 11261: 11257: 11252: 11248: 11238: 11235: 11233: 11230: 11228: 11225: 11223: 11220: 11218: 11215: 11213: 11212:Nonhypotenuse 11210: 11209: 11206: 11199: 11195: 11185: 11182: 11180: 11177: 11175: 11172: 11170: 11167: 11165: 11162: 11161: 11158: 11151: 11147: 11137: 11134: 11132: 11129: 11127: 11124: 11122: 11119: 11117: 11114: 11112: 11109: 11107: 11104: 11102: 11099: 11098: 11095: 11090: 11085: 11081: 11071: 11068: 11066: 11063: 11061: 11058: 11056: 11053: 11051: 11048: 11047: 11044: 11037: 11033: 11023: 11020: 11018: 11015: 11013: 11010: 11008: 11005: 11003: 11000: 10998: 10995: 10993: 10990: 10989: 10986: 10981: 10975: 10971: 10961: 10958: 10956: 10953: 10951: 10950:Perfect power 10948: 10946: 10943: 10941: 10940:Seventh power 10938: 10936: 10933: 10931: 10928: 10926: 10923: 10921: 10918: 10916: 10913: 10911: 10908: 10906: 10903: 10901: 10898: 10896: 10893: 10892: 10889: 10884: 10879: 10875: 10871: 10863: 10858: 10856: 10851: 10849: 10844: 10843: 10840: 10833: 10828: 10824: 10822: 10819: 10816: 10812: 10807: 10806: 10801: 10798: 10793: 10787: 10786: 10780: 10779: 10769: 10764: 10760: 10755: 10749: 10748: 10742: 10739: 10735: 10731: 10725: 10721: 10717: 10716: 10710: 10706: 10702: 10701: 10693: 10688: 10685: 10681: 10678: 10672: 10668: 10667: 10661: 10658: 10656:0-7167-1924-X 10652: 10648: 10644: 10640: 10636: 10635: 10630: 10626: 10623: 10619: 10615: 10612: 10609: 10605: 10601: 10597: 10596: 10584: 10580: 10575: 10570: 10565: 10560: 10556: 10552: 10548: 10541: 10534: 10530: 10526: 10522: 10518: 10514: 10509: 10504: 10500: 10496: 10489: 10483: 10479: 10475: 10471: 10467: 10462: 10453: 10448: 10441: 10432: 10427: 10420: 10406:on 2020-01-31 10405: 10401: 10395: 10384: 10377: 10368: 10363: 10356: 10348: 10344: 10340: 10336: 10329: 10322: 10315: 10311: 10307: 10303: 10296: 10288: 10283: 10279: 10275: 10271: 10267: 10260: 10254: 10251: 10245: 10238: 10235: 10229: 10222:(4): 589–604. 10221: 10217: 10210: 10203: 10194: 10188: 10183: 10174: 10169: 10165: 10161: 10154: 10148:, Example 3.1 10146: 10142: 10138: 10134: 10130: 10126: 10121: 10116: 10112: 10108: 10101: 10093: 10089: 10085: 10081: 10077: 10073: 10066: 10059: 10055: 10045: 10042: 10040: 10037: 10035: 10032: 10030: 10027: 10025: 10022: 10020: 10017: 10015: 10012: 10010: 10007: 10005: 10002: 10000: 9997: 9995: 9992: 9990: 9987: 9985: 9982: 9980: 9977: 9975: 9972: 9970: 9967: 9965: 9962: 9960: 9959:Associahedron 9957: 9956: 9951: 9945: 9940: 9907: 9902: 9897: 9893: 9886: 9883: 9880: 9874: 9871: 9867: 9856: 9853: 9850: 9844: 9838: 9835: 9832: 9828: 9821: 9818: 9815: 9809: 9806: 9797: 9793: 9786: 9783: 9780: 9774: 9771: 9760: 9756: 9749: 9746: 9743: 9737: 9734: 9728: 9722: 9719: 9716: 9707: 9704: 9701: 9695: 9679: 9674: 9669: 9665: 9661: 9658: 9655: 9651: 9640: 9637: 9634: 9628: 9622: 9619: 9616: 9612: 9608: 9605: 9602: 9593: 9590: 9587: 9583: 9579: 9576: 9573: 9567: 9559: 9556: 9553: 9549: 9545: 9542: 9539: 9533: 9527: 9524: 9521: 9512: 9509: 9506: 9500: 9490: 9485: 9478: 9474: 9469: 9465: 9458: 9454: 9449: 9441: 9438: 9433: 9429: 9425: 9422: 9419: 9414: 9410: 9404: 9401: 9396: 9392: 9388: 9385: 9382: 9377: 9373: 9366: 9358: 9357: 9356: 9353: 9349: 9334: 9332: 9327: 9311: 9307: 9284: 9280: 9271: 9267: 9266:Coxeter group 9263: 9259: 9245: 9225: 9222: 9219: 9216: 9213: 9193: 9190: 9187: 9167: 9164: 9161: 9152: 9150: 9146: 9142: 9123: 9120: 9117: 9114: 9111: 9105: 9102: 9099: 9091: 9085: 9082: 9076: 9070: 9067: 9052: 9044: 9025: 9021: 9012: 9002: 8985: 8979: 8976: 8953: 8950: 8944: 8941: 8918: 8915: 8909: 8906: 8897: 8895: 8893: 8889: 8885: 8880: 8878: 8873: 8871: 8867: 8863: 8859: 8851: 8846: 8837: 8820: 8817: 8812: 8806: 8801: 8796: 8791: 8784: 8779: 8774: 8769: 8762: 8757: 8752: 8747: 8740: 8735: 8730: 8725: 8719: 8707: 8706: 8691: 8688: 8683: 8677: 8672: 8667: 8660: 8655: 8650: 8643: 8638: 8633: 8627: 8615: 8614: 8599: 8596: 8591: 8585: 8580: 8573: 8568: 8562: 8550: 8549: 8534: 8531: 8526: 8520: 8514: 8502: 8501: 8500: 8496: 8486: 8482: 8476: 8459: 8456: 8451: 8445: 8440: 8435: 8430: 8423: 8418: 8413: 8408: 8401: 8396: 8391: 8386: 8379: 8374: 8369: 8364: 8358: 8346: 8345: 8344: 8340: 8328: 8324: 8320: 8313: 8309: 8288: 8285: 8280: 8274: 8269: 8264: 8259: 8252: 8247: 8242: 8237: 8230: 8225: 8220: 8215: 8208: 8203: 8198: 8193: 8187: 8175: 8174: 8173: 8169: 8160: 8153: 8149: 8145: 8138: 8134: 8128: 8127:Hankel matrix 8124: 8120: 8112:Hankel matrix 8109: 8095: 8075: 8072: 8069: 8046: 8042: 8038: 8027: 8023: 8020: 8017: 8014: 7999: 7996: 7993: 7990: 7986: 7963: 7960: 7957: 7954: 7934: 7914: 7911: 7908: 7879: 7875: 7872: 7869: 7866: 7836: 7833: 7830: 7827: 7824: 7804: 7784: 7781: 7778: 7758: 7738: 7729: 7535: 7532: 7529: 7509: 7506: 7503: 7495: 7479: 7476: 7473: 7453: 7450: 7447: 7427: 7407: 7399: 7394: 7392: 7388: 7356: 7352: 7349: 7334: 7331: 7328: 7324: 7319: 7314: 7310: 7302: 7301: 7278: 7274: 7271: 7268: 7265: 7253: 7242: 7238: 7235: 7223: 7220: 7215: 7211: 7203: 7202: 7179: 7175: 7172: 7169: 7166: 7154: 7149: 7145: 7141: 7138: 7133: 7129: 7121: 7120: 7097: 7093: 7090: 7087: 7084: 7072: 7067: 7063: 7059: 7054: 7050: 7046: 7039: 7038: 7037: 7016: 7011: 7008: 7005: 7001: 6992: 6988: 6984: 6979: 6975: 6971: 6963: 6958: 6955: 6952: 6948: 6944: 6939: 6936: 6933: 6929: 6922: 6918: 6912: 6907: 6904: 6901: 6897: 6893: 6888: 6885: 6882: 6878: 6872: 6868: 6862: 6857: 6854: 6851: 6847: 6843: 6840: 6835: 6832: 6829: 6825: 6821: 6816: 6813: 6810: 6806: 6798: 6797: 6796: 6777: 6774: 6771: 6767: 6755: 6751: 6748: 6745: 6742: 6728: 6723: 6720: 6717: 6713: 6709: 6704: 6701: 6698: 6694: 6690: 6685: 6682: 6679: 6675: 6667: 6666: 6665: 6608: 6585: 6580: 6577: 6574: 6570: 6564: 6560: 6554: 6549: 6546: 6543: 6539: 6535: 6532: 6527: 6524: 6521: 6517: 6509: 6508: 6507: 6493: 6486: 6483: 6459: 6453: 6421: 6417: 6414: 6402: 6397: 6393: 6338: 6312: 6309: 6306: 6295: 6292: 6289: 6285: 6278: 6274: 6268: 6263: 6260: 6257: 6253: 6249: 6244: 6241: 6238: 6234: 6223: 6220: 6215: 6211: 6203: 6202: 6201: 6185: 6181: 6158: 6154: 6145: 6141: 6134: 6131: 6093: 6089: 6080: 6070: 6056: 6053: 6048: 6044: 6020: 6017: 6014: 6011: 6008: 6002: 5999: 5996: 5993: 5987: 5984: 5981: 5975: 5972: 5969: 5966: 5958: 5954: 5950: 5944: 5941: 5936: 5930: 5927: 5914: 5913: 5912: 5895: 5892: 5886: 5883: 5880: 5877: 5871: 5868: 5863: 5859: 5855: 5852: 5849: 5843: 5840: 5837: 5834: 5828: 5825: 5819: 5816: 5810: 5807: 5801: 5798: 5788: 5787: 5786: 5783: 5769: 5764: 5760: 5756: 5751: 5748: 5745: 5741: 5734: 5731: 5728: 5723: 5720: 5717: 5714: 5684: 5681: 5678: 5674: 5667: 5664: 5661: 5655: 5650: 5646: 5639: 5636: 5633: 5630: 5620: 5619: 5618: 5615: 5604: 5599: 5595: 5591: 5583: 5573: 5569: 5565: 5561: 5553: 5545: 5535: 5530: 5526: 5519: 5515: 5504: 5490: 5487: 5484: 5461: 5453: 5449: 5442: 5428:be the first 5413: 5409: 5379: 5375: 5372: 5353: 5346: 5339: 5333: 5319: 5308: 5304: 5301: 5286: 5283: 5280: 5276: 5271: 5266: 5262: 5231: 5227: 5224: 5200: 5195: 5189: 5182: 5172: 5170: 5166: 5162: 5142: 5133: 5129: 5109: 5105: 5087: 5080: 5076: 5073: 5072: 5071: 5064: 5062: 5058: 5049: 5045: 5041: 5037: 5030: 5019: 4994: 4983: 4979: 4976: 4961: 4958: 4955: 4951: 4946: 4934: 4931: 4928: 4923: 4920: 4908: 4897: 4893: 4890: 4878: 4873: 4869: 4861: 4860: 4859: 4833: 4830: 4827: 4822: 4819: 4807: 4795: 4792: 4789: 4784: 4781: 4769: 4757: 4754: 4751: 4746: 4743: 4740: 4737: 4734: 4731: 4728: 4712: 4711: 4710: 4707: 4703: 4699: 4691: 4687: 4679: 4675: 4667: 4663:up steps and 4660: 4654: 4647: 4643: 4641: 4616: 4612: 4609: 4590: 4575: 4571: 4560: 4556: 4548: 4544: 4537: 4532: 4522: 4509: 4503: 4499: 4487: 4483: 4480: 4465: 4462: 4459: 4455: 4443: 4440: 4437: 4433: 4429: 4423: 4420: 4413: 4410: 4407: 4404: 4399: 4396: 4390: 4384: 4378: 4354: 4348: 4345: 4342: 4338: 4326: 4322: 4319: 4304: 4301: 4298: 4294: 4282: 4279: 4276: 4272: 4268: 4263: 4260: 4257: 4253: 4246: 4243: 4240: 4234: 4231: 4228: 4220: 4214: 4211: 4205: 4192: 4189: 4186: 4182: 4178: 4176: 4166: 4163: 4160: 4156: 4149: 4143: 4140: 4137: 4129: 4126: 4120: 4117: 4114: 4111: 4103: 4100: 4097: 4093: 4079: 4076: 4073: 4069: 4065: 4060: 4057: 4054: 4046: 4043: 4040: 4031: 4025: 4022: 4019: 4011: 4008: 4005: 4001: 3995: 3992: 3986: 3983: 3980: 3977: 3969: 3961: 3958: 3942: 3939: 3936: 3932: 3928: 3925: 3923: 3913: 3905: 3902: 3899: 3890: 3887: 3882: 3878: 3872: 3869: 3863: 3860: 3857: 3854: 3846: 3843: 3840: 3832: 3829: 3813: 3810: 3807: 3803: 3799: 3796: 3791: 3783: 3780: 3777: 3763: 3759: 3755: 3751: 3732: 3729: 3726: 3722: 3718: 3715: 3713: 3706: 3703: 3700: 3697: 3692: 3689: 3677: 3676: 3656: 3653: 3647: 3641: 3636: 3630: 3622: 3617: 3613: 3605: 3604: 3603: 3582: 3579: 3572: 3569: 3566: 3563: 3558: 3555: 3549: 3543: 3537: 3514: 3511: 3504: 3501: 3498: 3495: 3490: 3487: 3481: 3475: 3469: 3462: 3461: 3460: 3458: 3450: 3444: 3440: 3435: 3416: 3411: 3403: 3397: 3394: 3391: 3388: 3385: 3379: 3373: 3366: 3365: 3364: 3347: 3342: 3338: 3332: 3328: 3317: 3314: 3311: 3307: 3303: 3297: 3291: 3284: 3283: 3282: 3280: 3275: 3269: 3260: 3248: 3241: 3237: 3233: 3232: 3231: 3210: 3207: 3204: 3193: 3190: 3187: 3183: 3176: 3172: 3166: 3161: 3158: 3155: 3151: 3147: 3142: 3139: 3136: 3132: 3121: 3118: 3113: 3109: 3101: 3100: 3099: 3098: 3095: 3085: 3083: 3079: 3052: 3048: 3045: 3030: 3027: 3024: 3020: 3015: 3010: 3006: 2998: 2997: 2996: 2973: 2965: 2937: 2934: 2931: 2928: 2925: 2922: 2919: 2916: 2913: 2910: 2907: 2904: 2901: 2898: 2895: 2892: 2889: 2886: 2883: 2880: 2877: 2874: 2871: 2868: 2865: 2862: 2859: 2839: 2836: 2833: 2813: 2793: 2773: 2753: 2727: 2723: 2715: 2714: 2707: 2698: 2688: 2682: 2678: 2674: 2673: 2666: 2416: 2402: 2399: 2396: 2393: 2386: 2385: 2381: 2344: 2330: 2327: 2324: 2321: 2314: 2313: 2309: 2306: 2292: 2289: 2286: 2283: 2276: 2275: 2271: 2268: 2254: 2251: 2248: 2245: 2238: 2237: 2217: 2213: 2209: 2208: 2204: 2195: 2180: 2176: 2172: 2167: 2159: 2155: 2150: 2140: 2136: 2131: 2130: 2123: 2117: 2111: 2107: 2103: 2098: 2091: 2086: 2080: 2072: 2068: 2064: 2056: 2052: 2048: 2044: 2040: 2036: 2032: 2010: 2006: 1999: 1995: 1988: 1985:) = (1, ..., 1984: 1980: 1975: 1965: 1959: 1955: 1949: 1945: 1941: 1940: 1936: 1927: 1920: 1916: 1907: 1903: 1902:line segments 1899: 1893: 1888: 1884: 1883: 1878: 1874: 1868: 1864: 1860: 1849: 1845: 1840: 1839:lattice paths 1834: 1830: 1826: 1823: 1817: 1813: 1808: 1802: 1797: 1791: 1787: 1783: 1782: 1774: 1773:associahedron 1769: 1762: 1749: 1744: 1738: 1734: 1728: 1724: 1720: 1716: 1711: 1707: 1706: 1695: 1690: 1686: 1679: 1675: 1674:parenthesized 1669: 1662: 1658: 1654: 1653: 1638: 1634: 1629: 1625: 1624: 1597: 1592: 1586: 1580: 1576: 1572: 1571: 1568: 1564: 1551: 1547: 1540: 1530: 1525: 1521: 1517: 1516:combinatorics 1507: 1493: 1490: 1483: 1480: 1477: 1474: 1470: 1464: 1460: 1447: 1444: 1441: 1437: 1414: 1410: 1389: 1386: 1383: 1380: 1370: 1356: 1353: 1346: 1342: 1336: 1332: 1319: 1316: 1313: 1309: 1285: 1282: 1279: 1271: 1267: 1263: 1260: 1253: 1250: 1246: 1240: 1235: 1232: 1228: 1222: 1218: 1212: 1209: 1204: 1200: 1197: 1190: 1186: 1183: 1180: 1171: 1167: 1161: 1156: 1152: 1145: 1142: 1138: 1133: 1128: 1124: 1116: 1115: 1114: 1111: 1104: 1094: 1087: 1080: 1076: 1070: 1068: 1052: 1049: 1041: 1037: 1032: 1010: 1001: 994: 990: 986: 982: 975: 971: 965: 960: 956: 932: 929: 926: 915: 912: 909: 905: 898: 895: 892: 884: 881: 878: 875: 869: 863: 858: 854: 843: 840: 835: 831: 823: 822: 821: 804: 801: 798: 787: 784: 781: 777: 771: 768: 765: 761: 755: 750: 747: 744: 740: 736: 731: 727: 716: 713: 708: 704: 696: 695: 694: 693: 688: 687:; see below. 686: 667: 655: 651: 648: 645: 642: 627: 624: 621: 618: 614: 609: 604: 600: 592: 591: 590: 587: 585: 581: 575: 571: 545: 541: 538: 521: 518: 515: 511: 505: 492: 489: 486: 481: 478: 445: 441: 438: 435: 406: 403: 400: 395: 392: 380: 369: 365: 362: 350: 345: 341: 333: 332: 331: 327: 323: 309: 304: 296: 295: 294: 290: 270: 267: 264: 253: 249: 246: 243: 235: 230: 227: 224: 216: 210: 207: 203: 197: 194: 191: 183: 177: 174: 165: 154: 150: 147: 132: 129: 126: 122: 117: 112: 108: 100: 99: 98: 96: 87: 85: 81: 77: 73: 69: 65: 61: 57: 49: 46: 42: 30: 26: 22: 12494:Transposable 12358:Narcissistic 12265:Digital root 12185:Super-Poulet 12145:Jordan–PĂłlya 12094:prime factor 11999:Noncototient 11966:Almost prime 11948:Superperfect 11923:Refactorable 11918:Quasiperfect 11893:Hyperperfect 11734:Pseudoprimes 11705:Wall–Sun–Sun 11640:Ordered Bell 11610:Fuss–Catalan 11584: 11522:non-centered 11472:Dodecahedral 11449:non-centered 11335:non-centered 11237:Wolstenholme 10982:× 2 ± 1 10979: 10978:Of the form 10945:Eighth power 10925:Fourth power 10813:Davis, Tom: 10803: 10784: 10758: 10746: 10714: 10704: 10698: 10665: 10633: 10621: 10599: 10554: 10550: 10540: 10498: 10494: 10488: 10482:math/0505518 10469: 10466:Sergey Fomin 10461: 10440: 10419: 10408:. Retrieved 10404:the original 10394: 10376: 10355: 10341:(1): 35–40. 10338: 10334: 10321: 10305: 10301: 10295: 10269: 10265: 10259: 10249: 10244: 10236: 10233: 10228: 10219: 10215: 10202: 10193: 10182: 10163: 10159: 10153: 10110: 10106: 10100: 10078:(1): 52–53. 10075: 10071: 10058: 9999:Lobb numbers 9351: 9347: 9341:The Catalan 9340: 9328: 9262:Sergey Fomin 9260: 9153: 9140: 9053: 9042: 9008: 8969:in terms of 8898: 8894: 8891: 8881: 8877:John Riordan 8874: 8870:DĂ©sirĂ© AndrĂ© 8855: 8849: 8835: 8494: 8484: 8480: 8477: 8474: 8338: 8326: 8322: 8318: 8311: 8307: 8303: 8167: 8151: 8147: 8143: 8136: 8132: 8122: 8118: 8115: 7730: 7397: 7395: 7384: 7031: 6794: 6600: 6336: 6328: 6120:. Since any 6076: 6035: 5910: 5784: 5702: 5616: 5605: 5597: 5593: 5589: 5581: 5574: 5567: 5563: 5559: 5551: 5543: 5536: 5528: 5524: 5517: 5513: 5510: 5507:Fourth proof 5354: 5344: 5337: 5334: 5198: 5193: 5187: 5180: 5173: 5168: 5164: 5160: 5140: 5138: 5114: 5099: 5078: 5065: 5060: 5056: 5054: 5039: 5035: 5028: 5025: 5009: 4857: 4708: 4701: 4697: 4689: 4685: 4677: 4673: 4665: 4658: 4652: 4648: 4644: 4639: 4588: 4573: 4569: 4566: 4558: 4554: 4546: 4542: 4525:Second proof 3678: 3672: 3601: 3442: 3438: 3434:power series 3431: 3362: 3276: 3267: 3258: 3255: 3246: 3239: 3235: 3225: 3091: 3075: 2994: 2964:Bell numbers 2696: 2695:1, 2, ..., 2 2680: 2676: 2215: 2211: 2193: 2178: 2174: 2165: 2157: 2153: 2138: 2134: 2128: 2121: 2109: 2105: 2096: 2089: 2078: 2070: 2066: 2054: 2050: 2046: 2042: 2038: 2034: 2030: 2008: 2004: 1997: 1993: 1986: 1982: 1978: 1963: 1958:permutations 1947: 1943: 1925: 1918: 1914: 1891: 1872: 1858: 1855: 1847: 1843: 1832: 1828: 1815: 1811: 1800: 1789: 1785: 1747: 1736: 1732: 1726: 1722: 1718: 1714: 1693: 1687:, as in the 1667: 1660: 1656: 1636: 1632: 1590: 1578: 1574: 1566: 1562: 1538: 1528: 1519: 1513: 1371: 1300: 1112: 1102: 1092: 1085: 1078: 1074: 1071: 1033: 947: 819: 689: 682: 588: 573: 569: 460: 325: 321: 318: 288: 285: 88: 59: 53: 25: 12515:Extravagant 12510:Equidigital 12465:permutation 12424:Palindromic 12398:Automorphic 12296:Sum-product 12275:Sum-product 12230:Persistence 12125:ErdƑs–Woods 12047:Untouchable 11928:Semiperfect 11878:Hemiperfect 11539:Tesseractic 11477:Icosahedral 11457:Tetrahedral 11388:Dodecagonal 11089:Recursively 10960:Prime power 10935:Sixth power 10930:Fifth power 10910:Power of 10 10868:Classes of 10160:Mathematics 9684: even, 9270:root system 8836:et cetera. 8159:determinant 7492:dominating 7440:Y's, where 7391:cycle lemma 7381:Sixth proof 6073:Fifth proof 5022:Third proof 4551:instead of 3088:First proof 2986:is missing. 2149:Bell number 2118:of the set 1904:(a form of 1822:parse trees 1678:associating 1628:parenthesis 685:cycle lemma 76:recursively 12776:Categories 12727:Graphemics 12600:Pernicious 12454:Undulating 12429:Pandigital 12403:Trimorphic 12004:Nontotient 11853:Arithmetic 11467:Octahedral 11368:Heptagonal 11358:Pentagonal 11343:Triangular 11184:SierpiƄski 11106:Jacobsthal 10905:Power of 3 10900:Power of 2 10768:2008.00133 10686:95:96–102. 10593:References 10508:1809.07523 10452:2008.00133 10410:2014-06-24 10367:2105.07884 10187:Dyck paths 10177:,Theorem 1 10120:1809.07523 9912: odd. 9145:Ira Gessel 8852:volume III 7398:dominating 7387:Dyck words 6079:Dyck words 5141:reversible 5128:diagonal. 5057:exceedance 4581:right and 4529:See also: 2852:these are 2164:{1, ..., 2 2129:A fortiori 1972:is called 1956:-sortable 1587:of length 1585:Dyck words 315:Properties 300:(sequence 48:partitions 12484:Parasitic 12333:Factorion 12260:Digit sum 12252:Digit sum 12070:Fortunate 12057:Primorial 11971:Semiprime 11908:Practical 11873:Descartes 11868:Deficient 11858:Betrothed 11700:Wieferich 11529:Pentatope 11492:pyramidal 11383:Decagonal 11378:Nonagonal 11373:Octagonal 11363:Hexagonal 11222:Practical 11169:Congruent 11101:Fibonacci 11065:Loeschian 10805:MathWorld 10564:1209.6270 10557:: 35–55. 10533:214165563 10431:1208.4196 10166:(3): 40, 10145:214165563 10029:Semiorder 9884:− 9845:⋯ 9747:− 9729:⋯ 9629:⋯ 9557:− 9534:⋯ 9466:⋯ 9439:≥ 9423:… 9386:⋯ 9367:∑ 8986:α 8980:⁡ 8954:α 8945:⁡ 8919:α 8910:⁡ 8872:in 1887. 7533:− 7477:− 7254:− 7155:− 7060:− 7009:− 6985:− 6949:∑ 6937:− 6898:∑ 6894:− 6886:− 6848:∑ 6822:− 6775:− 6714:∑ 6691:− 6578:− 6540:∑ 6310:≥ 6303:for  6293:− 6254:∑ 6000:− 5973:− 5884:− 5841:− 5749:− 5721:− 4909:− 4793:− 4755:− 4732:− 4449:∞ 4434:∑ 4408:− 4400:− 4288:∞ 4273:∑ 4198:∞ 4183:∑ 4118:− 4085:∞ 4070:∑ 4041:− 3984:− 3959:− 3948:∞ 3933:∑ 3929:− 3900:− 3861:− 3844:− 3830:− 3819:∞ 3804:∑ 3800:− 3778:− 3738:∞ 3723:∑ 3719:− 3701:− 3693:− 3634:→ 3567:− 3559:− 3499:− 3323:∞ 3308:∑ 3208:≥ 3201:for  3191:− 3152:∑ 2120:{1, ..., 2077:{1, ..., 1962:{1, ..., 1898:triangles 1453:∞ 1438:∑ 1325:∞ 1310:∑ 1264:− 1233:− 1229:∫ 1213:π 1184:− 1153:∫ 1146:π 1002:π 966:∼ 923:for  913:− 882:− 795:for  785:− 769:− 741:∑ 439:≥ 381:− 268:≥ 261:for  221:∏ 12556:Friedman 12489:Primeval 12434:Repdigit 12391:-related 12338:Kaprekar 12312:Meertens 12235:Additive 12222:dynamics 12130:Friendly 12042:Sociable 12032:Amicable 11843:Abundant 11823:dynamics 11645:Schröder 11635:Narayana 11605:Eulerian 11595:Delannoy 11590:Dedekind 11411:centered 11277:centered 11164:Amenable 11121:Narayana 11111:Leonardo 11007:Mersenne 10955:Powerful 10895:Achilles 10631:(1988), 10583:15430707 10272:: 9–28, 10092:27646275 9936:See also 8888:Mingantu 8343:we have 8172:we have 8088:X's and 7927:X's and 7797:X's and 7751:X's and 7420:X's and 6487:′ 5911:we have 5785:Because 5165:starting 5061:vertical 5014:X's and 4700:− 1) × ( 3094:Segner's 1991:, where 1602:X's and 84:Minggatu 64:sequence 12729:related 12693:related 12657:related 12655:Sorting 12540:Vampire 12525:Harshad 12467:related 12439:Repunit 12353:Lychrel 12328:Dudeney 12180:StĂžrmer 12175:Sphenic 12160:Regular 12098:divisor 12037:Perfect 11933:Sublime 11903:Perfect 11630:Motzkin 11585:Catalan 11126:Padovan 11060:Leyland 11055:Idoneal 11050:Hilbert 11022:Woodall 10738:1676282 10643:Bibcode 10620:(1996) 10525:4052255 10137:4052255 9051:votes. 8840:History 6340:, i.e. 5079:touches 3445:+ 1 = 0 2966:, only 2826:). For 2667:5 ways 2608:/\/\/\, 2382:2 ways 2058:, with 1088:= 2 − 1 580:integer 306:in the 303:A000108 12595:Odious 12520:Frugal 12474:Cyclic 12463:Digit- 12170:Smooth 12155:Pronic 12115:Cyclic 12092:Other 12065:Euclid 11715:Wilson 11689:Primes 11348:Square 11217:Polite 11179:Riesel 11174:Knödel 11136:Perrin 11017:Thabit 11002:Fermat 10992:Cullen 10915:Square 10883:Powers 10736:  10726:  10707:: 5–7. 10673:  10653:  10614:Conway 10606:  10581:  10531:  10523:  10253:online 10143:  10135:  10090:  9355:, is: 9143:, per 8129:whose 5703:Write 5401:. Let 4371:Thus, 2310:1 way 2272:1 way 2012:where 1596:string 578:is an 62:are a 58:, the 12636:Prime 12631:Lucky 12620:sieve 12549:Other 12535:Smith 12415:Digit 12373:Happy 12348:Keith 12321:Other 12165:Rough 12135:Giuga 11600:Euler 11462:Cubic 11116:Lucas 11012:Proth 10789:(PDF) 10763:arXiv 10751:(PDF) 10695:(PDF) 10579:S2CID 10559:arXiv 10529:S2CID 10503:arXiv 10478:arXiv 10447:arXiv 10426:arXiv 10386:(PDF) 10362:arXiv 10331:(PDF) 10212:(PDF) 10141:S2CID 10115:arXiv 10088:JSTOR 10068:(PDF) 10051:Notes 8884:China 7728:are. 6664:, so 6644:than 6506:, so 6384:, so 5617:Thus 5579:with 5541:with 5169:below 4688:− 1, 4545:– 1, 3447:as a 2368:/\/\, 2187:with 1954:stack 1889:with 1798:with 1745:with 1743:trees 1065:, or 1038:, by 12590:Evil 12270:Self 12220:and 12110:Blum 11821:and 11625:Lobb 11580:Cake 11575:Bell 11325:Star 11232:Ulam 11131:Pell 10920:Cube 10724:ISBN 10671:ISBN 10651:ISBN 10616:and 10604:ISBN 9238:and 9154:For 8934:and 8807:1430 8157:has 8116:The 7692:and 7451:> 6364:and 6329:Let 5592:+ 2) 5562:+ 2) 5522:and 5161:last 4704:+ 1) 4692:+ 1) 4549:+ 1) 3277:The 3265:and 2974:1213 2938:1111 2932:1112 2926:1121 2920:1122 2914:1123 2908:1211 2902:1212 2896:1221 2890:1222 2884:1223 2878:1231 2872:1232 2866:1233 2860:1234 2630:\/\, 2586:/\/\ 2147:-th 2037:) = 2024:and 2020:and 1771:The 1567:down 1565:and 1557:and 1544:= 14 1536:and 1100:and 1042:for 930:> 820:and 802:> 428:for 308:OEIS 293:are 89:The 38:= 42 32:The 12708:Ban 12096:or 11615:Lah 10618:Guy 10569:doi 10513:doi 10499:343 10343:doi 10310:doi 10282:hdl 10274:doi 10168:doi 10125:doi 10111:343 10080:doi 9045:+ 1 8977:sin 8942:sin 8907:sin 8802:429 8797:132 8785:429 8780:132 8763:132 8715:det 8678:132 8623:det 8558:det 8510:det 8497:+ 1 8446:429 8441:132 8424:132 8354:det 8341:= 4 8275:132 8183:det 8170:= 4 6472:or 6229:and 5600:+ 1 5584:+ 3 5554:+ 1 5546:+ 2 5350:= 5 5340:= 3 5201:+ 1 5194:all 5190:− 2 5183:− 1 5119:to 5031:+ 1 4668:− 1 4661:+ 1 4640:bad 3627:lim 3451:of 3238:= X 3127:and 2786:or 2612:/\/ 2307:/\ 2196:= 4 2151:. 2099:= 4 2092:= 3 2009:unv 1976:if 1960:of 1928:= 4 1894:+ 2 1861:= 4 1803:+ 1 1750:+ 1 1696:= 3 1670:+ 1 1534:= 5 1402:is 1108:= 5 1098:= 2 849:and 722:and 330:is 97:by 66:of 54:In 12778:: 10802:. 10761:, 10734:MR 10732:, 10722:, 10705:32 10703:. 10697:. 10649:, 10641:, 10577:. 10567:. 10555:56 10553:. 10549:. 10527:, 10521:MR 10519:, 10511:, 10497:, 10472:, 10470:13 10339:11 10337:. 10333:. 10306:14 10304:, 10280:, 10270:31 10268:, 10220:56 10218:. 10214:. 10162:, 10139:, 10133:MR 10131:, 10123:, 10109:, 10086:. 10076:37 10074:. 10070:. 9350:= 9333:. 9001:. 8879:. 8792:42 8775:42 8770:14 8758:42 8753:14 8741:42 8736:14 8673:42 8668:14 8661:42 8656:14 8644:14 8586:14 8499:. 8483:× 8460:1. 8436:42 8431:14 8419:42 8414:14 8402:42 8397:14 8380:14 8329:−1 8310:, 8289:1. 8270:42 8265:14 8253:42 8248:14 8231:14 8154:−2 8135:, 8121:× 7656:, 7620:, 7036:, 6118:c' 5558:(4 5534:. 5531:+1 5503:. 4676:, 4572:× 4557:, 3441:− 3439:xc 3274:. 3211:0. 2664:\ 2647:\, 2619:\, 2567:/\ 2554:/\ 2519:/\ 2379:\ 2366:/\ 2269:* 2132:, 2126:. 2007:= 1885:A 1863:: 1846:× 1725:, 1721:, 1717:, 1611:XY 1563:up 1546:. 1506:. 1369:. 1110:. 1069:. 933:0. 586:. 310:). 271:0. 86:. 45:52 10980:a 10861:e 10854:t 10847:v 10808:. 10765:: 10645:: 10610:. 10585:. 10571:: 10561:: 10515:: 10505:: 10480:: 10455:. 10449:: 10434:. 10428:: 10413:. 10388:. 10370:. 10364:: 10349:. 10345:: 10312:: 10284:: 10276:: 10237:7 10170:: 10164:5 10127:: 10117:: 10094:. 10082:: 9908:m 9903:, 9898:2 9894:/ 9890:) 9887:1 9881:m 9878:( 9875:+ 9872:n 9868:C 9860:) 9857:m 9854:+ 9851:n 9848:( 9842:) 9839:1 9836:+ 9833:2 9829:/ 9825:) 9822:3 9819:+ 9816:m 9813:( 9810:+ 9807:n 9804:( 9801:) 9798:2 9794:/ 9790:) 9787:3 9784:+ 9781:m 9778:( 9775:+ 9772:n 9769:( 9764:) 9761:2 9757:/ 9753:) 9750:1 9744:m 9741:( 9738:+ 9735:n 9732:( 9726:) 9723:2 9720:+ 9717:n 9714:( 9711:) 9708:1 9705:+ 9702:n 9699:( 9696:m 9680:m 9675:, 9670:2 9666:/ 9662:m 9659:+ 9656:n 9652:C 9644:) 9641:m 9638:+ 9635:n 9632:( 9626:) 9623:3 9620:+ 9617:2 9613:/ 9609:m 9606:+ 9603:n 9600:( 9597:) 9594:2 9591:+ 9588:2 9584:/ 9580:m 9577:+ 9574:n 9571:( 9568:2 9563:) 9560:1 9554:2 9550:/ 9546:m 9543:+ 9540:n 9537:( 9531:) 9528:2 9525:+ 9522:n 9519:( 9516:) 9513:1 9510:+ 9507:n 9504:( 9501:m 9491:{ 9486:= 9479:m 9475:i 9470:C 9459:1 9455:i 9450:C 9442:0 9434:m 9430:i 9426:, 9420:, 9415:1 9411:i 9405:n 9402:= 9397:m 9393:i 9389:+ 9383:+ 9378:1 9374:i 9352:m 9348:k 9343:k 9312:n 9308:A 9285:n 9281:C 9246:4 9226:3 9223:, 9220:2 9217:= 9214:m 9194:n 9191:= 9188:m 9168:1 9165:= 9162:m 9124:! 9121:n 9118:! 9115:m 9112:! 9109:) 9106:n 9103:+ 9100:m 9097:( 9092:! 9089:) 9086:n 9083:2 9080:( 9077:! 9074:) 9071:m 9068:2 9065:( 9049:n 9043:n 9026:n 9022:C 8989:) 8983:( 8957:) 8951:4 8948:( 8922:) 8916:2 8913:( 8821:5 8818:= 8813:] 8748:5 8731:5 8726:2 8720:[ 8692:4 8689:= 8684:] 8651:5 8639:5 8634:2 8628:[ 8600:3 8597:= 8592:] 8581:5 8574:5 8569:2 8563:[ 8535:2 8532:= 8527:] 8521:2 8515:[ 8495:n 8490:2 8485:n 8481:n 8457:= 8452:] 8409:5 8392:5 8387:2 8375:5 8370:2 8365:1 8359:[ 8339:n 8334:n 8327:j 8325:+ 8323:i 8319:C 8314:) 8312:j 8308:i 8306:( 8286:= 8281:] 8260:5 8243:5 8238:2 8226:5 8221:2 8216:1 8209:5 8204:2 8199:1 8194:1 8188:[ 8168:n 8163:n 8152:j 8150:+ 8148:i 8144:C 8139:) 8137:j 8133:i 8131:( 8123:n 8119:n 8096:n 8076:1 8073:+ 8070:n 8047:n 8043:C 8039:= 8033:) 8028:n 8024:1 8021:+ 8018:n 8015:2 8009:( 8000:1 7997:+ 7994:n 7991:2 7987:1 7964:1 7961:+ 7958:n 7955:2 7935:n 7915:1 7912:+ 7909:n 7885:) 7880:n 7876:1 7873:+ 7870:n 7867:2 7861:( 7837:1 7834:+ 7831:n 7828:= 7825:m 7805:n 7785:1 7782:+ 7779:n 7759:n 7739:n 7714:X 7711:Y 7708:X 7705:X 7702:Y 7678:Y 7675:X 7672:X 7669:Y 7666:X 7642:X 7639:X 7636:Y 7633:X 7630:Y 7606:X 7603:Y 7600:X 7597:Y 7594:X 7570:Y 7567:X 7564:Y 7561:X 7558:X 7536:n 7530:m 7510:n 7507:+ 7504:m 7480:n 7474:m 7454:n 7448:m 7428:n 7408:m 7362:) 7357:i 7353:i 7350:2 7344:( 7335:1 7332:+ 7329:i 7325:1 7320:= 7315:i 7311:C 7284:) 7279:i 7275:1 7272:+ 7269:i 7266:2 7260:( 7248:) 7243:i 7239:i 7236:2 7230:( 7224:2 7221:= 7216:i 7212:C 7185:) 7180:i 7176:1 7173:+ 7170:i 7167:2 7161:( 7150:i 7146:B 7142:2 7139:= 7134:i 7130:C 7103:) 7098:i 7094:1 7091:+ 7088:i 7085:2 7079:( 7073:= 7068:i 7064:C 7055:i 7051:B 7047:2 7034:n 7017:. 7012:i 7006:n 7002:C 6998:) 6993:i 6989:C 6980:i 6976:B 6972:2 6969:( 6964:n 6959:0 6956:= 6953:i 6945:= 6940:i 6934:n 6930:C 6923:i 6919:C 6913:n 6908:0 6905:= 6902:i 6889:i 6883:n 6879:C 6873:i 6869:B 6863:n 6858:0 6855:= 6852:i 6844:2 6841:= 6836:1 6833:+ 6830:n 6826:C 6817:1 6814:+ 6811:n 6807:B 6778:i 6772:n 6768:C 6761:) 6756:i 6752:1 6749:+ 6746:i 6743:2 6737:( 6729:n 6724:0 6721:= 6718:i 6710:= 6705:1 6702:+ 6699:n 6695:C 6686:1 6683:+ 6680:n 6676:B 6652:) 6632:( 6612:) 6609:c 6586:. 6581:i 6575:n 6571:C 6565:i 6561:B 6555:n 6550:0 6547:= 6544:i 6536:2 6533:= 6528:1 6525:+ 6522:n 6518:B 6494:b 6491:( 6484:c 6480:) 6460:b 6457:) 6454:c 6451:( 6427:) 6422:n 6418:n 6415:2 6409:( 6403:= 6398:n 6394:B 6372:) 6352:( 6342:b 6337:n 6335:2 6331:b 6325:. 6313:0 6307:n 6296:i 6290:n 6286:C 6279:i 6275:C 6269:n 6264:0 6261:= 6258:i 6250:= 6245:1 6242:+ 6239:n 6235:C 6224:1 6221:= 6216:0 6212:C 6186:1 6182:c 6159:2 6155:c 6151:) 6146:1 6142:c 6138:( 6135:= 6132:c 6122:c 6114:c 6110:n 6094:n 6090:C 6057:1 6054:= 6049:0 6045:C 6021:. 6018:! 6015:! 6012:! 6009:! 6006:) 6003:2 5997:n 5994:4 5991:( 5988:= 5985:! 5982:! 5979:) 5976:1 5970:n 5967:2 5964:( 5959:n 5955:2 5951:= 5945:! 5942:n 5937:! 5934:) 5931:n 5928:2 5925:( 5896:! 5893:! 5890:) 5887:1 5881:n 5878:2 5875:( 5872:! 5869:n 5864:n 5860:2 5856:= 5853:! 5850:! 5847:) 5844:1 5838:n 5835:2 5832:( 5829:! 5826:! 5823:) 5820:n 5817:2 5814:( 5811:= 5808:! 5805:) 5802:n 5799:2 5796:( 5770:. 5765:n 5761:C 5757:= 5752:1 5746:n 5742:C 5735:1 5732:+ 5729:n 5724:2 5718:n 5715:4 5699:. 5685:1 5682:+ 5679:n 5675:C 5671:) 5668:2 5665:+ 5662:n 5659:( 5656:= 5651:n 5647:C 5643:) 5640:2 5637:+ 5634:n 5631:4 5628:( 5612:P 5608:Q 5598:n 5594:C 5590:n 5588:( 5582:n 5577:Q 5568:n 5564:C 5560:n 5552:n 5550:2 5544:n 5539:P 5529:n 5525:C 5518:n 5514:C 5491:F 5488:X 5485:L 5465:) 5462:L 5459:( 5454:d 5450:X 5446:) 5443:F 5440:( 5430:X 5414:d 5410:X 5385:) 5380:n 5376:n 5373:2 5367:( 5348:3 5345:C 5338:n 5320:. 5314:) 5309:n 5305:n 5302:2 5296:( 5287:1 5284:+ 5281:n 5277:1 5272:= 5267:n 5263:C 5237:) 5232:n 5228:n 5225:2 5219:( 5205:n 5199:n 5188:n 5181:n 5176:n 5157:X 5153:P 5149:n 5145:P 5125:1 5121:2 5117:3 5102:X 5096:. 5094:X 5090:X 5083:X 5068:1 5040:n 5036:C 5029:n 5016:n 5012:n 4995:. 4989:) 4984:n 4980:n 4977:2 4971:( 4962:1 4959:+ 4956:n 4952:1 4947:= 4941:) 4935:1 4932:+ 4929:n 4924:n 4921:2 4915:( 4903:) 4898:n 4894:n 4891:2 4885:( 4879:= 4874:n 4870:C 4840:) 4834:1 4831:+ 4828:n 4823:n 4820:2 4814:( 4808:= 4802:) 4796:1 4790:n 4785:n 4782:2 4776:( 4770:= 4764:) 4758:1 4752:n 4747:1 4744:+ 4741:n 4738:+ 4735:1 4729:n 4723:( 4702:n 4698:n 4696:( 4690:n 4686:n 4684:( 4680:) 4678:n 4674:n 4672:( 4666:n 4659:n 4653:n 4651:2 4622:) 4617:n 4613:n 4610:2 4604:( 4589:n 4587:2 4583:n 4579:n 4574:n 4570:n 4563:. 4561:) 4559:n 4555:n 4553:( 4547:n 4543:n 4541:( 4510:. 4504:n 4500:x 4493:) 4488:n 4484:n 4481:2 4475:( 4466:1 4463:+ 4460:n 4456:1 4444:0 4441:= 4438:n 4430:= 4424:x 4421:2 4414:x 4411:4 4405:1 4397:1 4391:= 4388:) 4385:x 4382:( 4379:c 4355:. 4349:1 4346:+ 4343:n 4339:x 4332:) 4327:n 4323:n 4320:2 4314:( 4305:1 4302:+ 4299:n 4295:2 4283:0 4280:= 4277:n 4269:= 4264:1 4261:+ 4258:n 4254:x 4247:! 4244:n 4241:! 4238:) 4235:1 4232:+ 4229:n 4226:( 4221:! 4218:) 4215:n 4212:2 4209:( 4206:2 4193:0 4190:= 4187:n 4179:= 4167:1 4164:+ 4161:n 4157:x 4150:! 4147:) 4144:1 4141:+ 4138:n 4135:( 4130:! 4127:! 4124:) 4121:1 4115:n 4112:2 4109:( 4104:1 4101:+ 4098:n 4094:2 4080:0 4077:= 4074:n 4066:= 4061:1 4058:+ 4055:n 4051:) 4047:x 4044:4 4038:( 4032:! 4029:) 4026:1 4023:+ 4020:n 4017:( 4012:1 4009:+ 4006:n 4002:2 3996:! 3993:! 3990:) 3987:1 3981:n 3978:2 3975:( 3970:n 3966:) 3962:1 3956:( 3943:0 3940:= 3937:n 3926:= 3914:n 3910:) 3906:x 3903:4 3897:( 3891:! 3888:n 3883:n 3879:2 3873:! 3870:! 3867:) 3864:3 3858:n 3855:2 3852:( 3847:1 3841:n 3837:) 3833:1 3827:( 3814:1 3811:= 3808:n 3797:= 3792:n 3788:) 3784:x 3781:4 3775:( 3769:) 3764:n 3760:2 3756:/ 3752:1 3746:( 3733:1 3730:= 3727:n 3716:= 3707:x 3704:4 3698:1 3690:1 3669:. 3657:1 3654:= 3651:) 3648:x 3645:( 3642:c 3637:0 3631:x 3623:= 3618:0 3614:C 3598:. 3583:x 3580:2 3573:x 3570:4 3564:1 3556:1 3550:= 3547:) 3544:x 3541:( 3538:c 3515:x 3512:2 3505:x 3502:4 3496:1 3491:+ 3488:1 3482:= 3479:) 3476:x 3473:( 3470:c 3453:c 3443:c 3417:; 3412:2 3408:) 3404:x 3401:( 3398:c 3395:x 3392:+ 3389:1 3386:= 3383:) 3380:x 3377:( 3374:c 3348:. 3343:n 3339:x 3333:n 3329:C 3318:0 3315:= 3312:n 3304:= 3301:) 3298:x 3295:( 3292:c 3271:2 3268:w 3262:1 3259:w 3250:2 3247:w 3245:Y 3243:1 3240:w 3236:w 3228:w 3205:n 3194:i 3188:n 3184:C 3177:i 3173:C 3167:n 3162:0 3159:= 3156:i 3148:= 3143:1 3140:+ 3137:n 3133:C 3122:1 3119:= 3114:0 3110:C 3058:) 3053:n 3049:n 3046:2 3040:( 3031:1 3028:+ 3025:n 3021:1 3016:= 3011:n 3007:C 2960:1 2956:1 2952:0 2935:, 2929:, 2923:, 2917:, 2911:, 2905:, 2899:, 2893:, 2887:, 2881:, 2875:, 2869:, 2863:, 2840:4 2837:= 2834:n 2814:1 2794:1 2774:0 2754:1 2744:n 2728:n 2724:C 2708:. 2702:n 2697:n 2691:n 2681:n 2677:C 2662:0 2659:0 2656:0 2653:0 2651:/ 2649:0 2645:0 2642:0 2639:0 2636:0 2634:/ 2632:0 2628:0 2625:0 2623:/ 2621:0 2617:0 2614:0 2610:0 2606:\ 2604:0 2601:0 2599:/ 2597:0 2594:0 2591:0 2588:0 2584:0 2581:0 2578:0 2575:0 2572:0 2569:0 2565:0 2562:0 2559:0 2556:0 2552:0 2549:0 2546:0 2543:0 2540:0 2537:0 2534:0 2531:0 2528:0 2525:0 2522:0 2517:0 2514:0 2511:0 2508:0 2505:0 2502:0 2499:0 2496:0 2493:0 2490:0 2487:0 2484:0 2481:0 2478:0 2475:0 2472:0 2469:0 2466:0 2463:0 2460:0 2457:0 2454:0 2451:0 2448:0 2445:0 2442:0 2439:0 2436:0 2433:0 2430:0 2427:0 2424:0 2421:0 2418:0 2403:: 2400:3 2397:= 2394:n 2377:0 2374:0 2372:/ 2370:0 2364:0 2361:0 2358:0 2355:0 2352:0 2349:0 2346:0 2331:: 2328:2 2325:= 2322:n 2293:: 2290:1 2287:= 2284:n 2255:: 2252:0 2249:= 2246:n 2226:n 2222:n 2216:n 2212:C 2198:: 2194:n 2189:n 2185:n 2179:n 2175:C 2168:} 2166:n 2158:n 2154:C 2145:n 2139:n 2135:C 2124:} 2122:n 2110:n 2106:C 2097:n 2090:n 2081:} 2079:n 2071:n 2067:C 2060:S 2055:n 2053:) 2051:v 2049:( 2047:S 2045:) 2043:u 2041:( 2039:S 2035:w 2033:( 2031:S 2026:v 2022:u 2018:w 2014:n 2005:w 2000:) 1998:w 1996:( 1994:S 1989:) 1987:n 1983:w 1981:( 1979:S 1970:w 1966:} 1964:n 1948:n 1944:C 1930:: 1926:n 1919:n 1915:C 1910:n 1892:n 1859:n 1848:n 1844:n 1833:n 1829:C 1816:n 1812:C 1801:n 1790:n 1786:C 1777:4 1754:n 1748:n 1737:n 1733:C 1727:d 1723:c 1719:b 1715:a 1694:n 1681:n 1668:n 1661:n 1657:C 1643:n 1637:n 1633:C 1604:n 1600:n 1591:n 1589:2 1579:n 1575:C 1559:) 1555:( 1542:4 1539:C 1532:3 1529:C 1494:1 1491:= 1484:1 1481:+ 1478:n 1475:2 1471:2 1465:n 1461:C 1448:0 1445:= 1442:n 1415:k 1411:C 1390:1 1387:+ 1384:k 1381:2 1357:2 1354:= 1347:n 1343:4 1337:n 1333:C 1320:0 1317:= 1314:n 1286:. 1283:t 1280:d 1272:2 1268:t 1261:1 1254:n 1251:2 1247:t 1241:1 1236:1 1223:n 1219:4 1210:2 1205:= 1201:x 1198:d 1191:x 1187:x 1181:4 1172:n 1168:x 1162:4 1157:0 1143:2 1139:1 1134:= 1129:n 1125:C 1106:3 1103:C 1096:2 1093:C 1086:n 1079:n 1075:C 1053:! 1050:n 1029:n 1025:n 1011:, 995:2 991:/ 987:3 983:n 976:n 972:4 961:n 957:C 927:n 916:1 910:n 906:C 899:1 896:+ 893:n 888:) 885:1 879:n 876:2 873:( 870:2 864:= 859:n 855:C 844:1 841:= 836:0 832:C 805:0 799:n 788:i 782:n 778:C 772:1 766:i 762:C 756:n 751:1 748:= 745:i 737:= 732:n 728:C 717:1 714:= 709:0 705:C 668:, 661:) 656:n 652:1 649:+ 646:n 643:2 637:( 628:1 625:+ 622:n 619:2 615:1 610:= 605:n 601:C 574:n 570:C 551:) 546:n 542:n 539:2 533:( 522:1 519:+ 516:n 512:n 506:= 499:) 493:1 490:+ 487:n 482:n 479:2 473:( 446:, 442:0 436:n 413:) 407:1 404:+ 401:n 396:n 393:2 387:( 375:) 370:n 366:n 363:2 357:( 351:= 346:n 342:C 326:n 322:C 289:n 265:n 254:k 250:k 247:+ 244:n 236:n 231:2 228:= 225:k 217:= 211:! 208:n 204:! 201:) 198:1 195:+ 192:n 189:( 184:! 181:) 178:n 175:2 172:( 166:= 160:) 155:n 151:n 148:2 142:( 133:1 130:+ 127:n 123:1 118:= 113:n 109:C 91:n 50:) 36:5 34:C 23:.

Index

Catalan's constant

noncrossing partitions
52
partitions
combinatorial mathematics
sequence
natural numbers
counting problems
recursively
EugĂšne Charles Catalan
Minggatu
central binomial coefficients
A000108
OEIS
integer
proof of the correctness of the formula
cycle lemma
recurrence relations
asymptotic growth of the central binomial coefficients
Stirling's approximation
via generating functions
combinatorics
Richard P. Stanley

Dyck words
string
parenthesis
parenthesized
associating

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