cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-18 of 18 results.

A355262 Array of Fuss-Catalan numbers read by ascending antidiagonals, A(n, k) = binomial(k*n + 1, k)/(k*n + 1).

Original entry on oeis.org

1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 2, 1, 0, 1, 1, 3, 5, 1, 0, 1, 1, 4, 12, 14, 1, 0, 1, 1, 5, 22, 55, 42, 1, 0, 1, 1, 6, 35, 140, 273, 132, 1, 0, 1, 1, 7, 51, 285, 969, 1428, 429, 1, 0, 1, 1, 8, 70, 506, 2530, 7084, 7752, 1430, 1, 0
Offset: 0

Views

Author

Peter Luschny, Jun 26 2022

Keywords

Comments

An alternative definition is: the Fuss-Catalan sequences (A(n, k), k >= 0 ) are the main diagonals of the Fuss-Catalan triangles of order n - 1. See A355173 for the definition of a Fuss-Catalan triangle.

Examples

			Array A(n, k) begins:
[0] 1, 1, 0,   0,    0,     0,      0,       0,         0, ...  A019590
[1] 1, 1, 1,   1,    1,     1,      1,       1,         1, ...  A000012
[2] 1, 1, 2,   5,   14,    42,    132,     429,      1430, ...  A000108
[3] 1, 1, 3,  12,   55,   273,   1428,    7752,     43263, ...  A001764
[4] 1, 1, 4,  22,  140,   969,   7084,   53820,    420732, ...  A002293
[5] 1, 1, 5,  35,  285,  2530,  23751,  231880,   2330445, ...  A002294
[6] 1, 1, 6,  51,  506,  5481,  62832,  749398,   9203634, ...  A002295
[7] 1, 1, 7,  70,  819, 10472, 141778, 1997688,  28989675, ...  A002296
[8] 1, 1, 8,  92, 1240, 18278, 285384, 4638348,  77652024, ...  A007556
[9] 1, 1, 9, 117, 1785, 29799, 527085, 9706503, 184138713, ...  A062994
		

References

  • N. I. Fuss, Solutio quaestionis, quot modis polygonum n laterum in polygona m laterum, per diagonales resolvi queat, Nova Acta Academiae Scientiarum Imperialis Petropolitanae, vol.9 (1791), 243-251.
  • R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics, Addison-Wesley, Reading, MA, 1990, (Eqs. 5.70, 7.66, and sec. 7.5, example 5).

Crossrefs

Variants: A062993, A070914.
Fuss-Catalan triangles: A123110 (order 0), A355173 (order 1), A355172 (order 2), A355174 (order 3).

Programs

  • Maple
    A := (n, k) -> binomial(k*n + 1, k)/(k*n + 1):
    for n from 0 to 9 do seq(A(n, k), k = 0..8) od;
  • Mathematica
    (* See the Knuth references. In the christmas lecture Knuth has fun calculating the Fuss-Catalan development of Pi and i. *)
    B[t_, n_] := Sum[Binomial[t k+1, k] z^k / (t k+1), {k, 0, n-1}] + O[z]^n
    Table[CoefficientList[B[n, 9], z], {n, 0, 9}] // TableForm

Formula

A(n, k) = (1/k!) * Product_{j=1..k-1} (k*n + 1 - j).
A(n, k) = (binomial(k*n, k) + binomial(k*n, k-1)) / (k*n + 1).
Let B(t, z) = Sum_{k>=0} binomial(k*t + 1, k)*z^k / (k*t + 1), then
A(n, k) = [z^k] B(n, z).

A370062 Array read by antidiagonals: T(n,k) is the number of achiral dissections of a polygon into n k-gons by nonintersecting diagonals, n >= 1, k >= 3.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 3, 2, 1, 1, 3, 4, 7, 5, 1, 1, 3, 5, 9, 12, 5, 1, 1, 4, 6, 18, 22, 30, 14, 1, 1, 4, 7, 21, 35, 52, 55, 14, 1, 1, 5, 8, 34, 51, 136, 140, 143, 42, 1, 1, 5, 9, 38, 70, 190, 285, 340, 273, 42, 1, 1, 6, 10, 55, 92, 368, 506, 1155, 969, 728, 132
Offset: 1

Views

Author

Andrew Howroyd, Feb 08 2024

Keywords

Comments

The polygon prior to dissection will have n*(k-2)+2 sides.

Examples

			Array begins:
=============================================
n\k|  3   4   5    6    7    8    9    10 ...
---+-----------------------------------------
1  |  1   1   1    1    1    1    1     1 ...
2  |  1   1   1    1    1    1    1     1 ...
3  |  1   2   2    3    3    4    4     5 ...
4  |  2   3   4    5    6    7    8     9 ...
5  |  2   7   9   18   21   34   38    55 ...
6  |  5  12  22   35   51   70   92   117 ...
7  |  5  30  52  136  190  368  468   775 ...
8  | 14  55 140  285  506  819 1240  1785 ...
9  | 14 143 340 1155 1950 4495 6545 12350 ...
  ...
		

Crossrefs

Columns are A208355(n-1), A047749 (k=4), A369472 (k=5), A143546 (k=6), A143547 (k=8), A143554 (k=10), A192893 (k=12).
Cf. A070914 (rooted), A295224 (oriented), A295260 (unoriented), A369929, A370060 (achiral rooted at cell).

Programs

  • PARI
    \\ here u is Fuss-Catalan sequence with p = k-1.
    u(n, k, r) = {r*binomial((k - 1)*n + r, n)/((k - 1)*n + r)}
    T(n, k) = {(if(n%2, u((n-1)/2, k, k\2), if(k%2, u(n/2-1, k, k-1), u(n/2, k, 1))))}
    for(n=1, 9, for(k=3, 10, print1(T(n, k), ", ")); print);

Formula

T(n,k) = 2*A295260(n,k) - A295224(n,k).
T(n,2*k+1) = A370060(n,2*k+1).
T(n,2*k) = A369929(n,2*k-1).

A361236 Array read by antidiagonals: T(n,k) is the number of noncrossing k-gonal cacti with n polygons up to rotation.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 5, 11, 1, 1, 1, 1, 8, 33, 49, 1, 1, 1, 1, 9, 63, 230, 204, 1, 1, 1, 1, 12, 105, 664, 1827, 984, 1, 1, 1, 1, 13, 159, 1419, 7462, 15466, 4807, 1, 1, 1, 1, 16, 221, 2637, 21085, 90896, 137085, 24739, 1
Offset: 0

Views

Author

Andrew Howroyd, Mar 05 2023

Keywords

Comments

The number of noncrossing k-gonal cacti is given by column 2*(k-1) of A070914. This sequence enumerates these cacti with rotations being considered equivalent.
Equivalently, T(n,k) is the number of connected acyclic k-uniform noncrossing antichains with n blocks covering (k-1)*n+1 nodes where the intersection of two blocks is at most 1 node modulo cyclic rotation of the nodes.
Noncrossing trees correspond to the case of k = 2.

Examples

			=====================================================
n\k | 1     2       3        4        5         6 ...
----+------------------------------------------------
  0 | 1     1       1        1        1         1 ...
  1 | 1     1       1        1        1         1 ...
  2 | 1     1       1        1        1         1 ...
  3 | 1     4       5        8        9        12 ...
  4 | 1    11      33       63      105       159 ...
  5 | 1    49     230      664     1419      2637 ...
  6 | 1   204    1827     7462    21085     48048 ...
  7 | 1   984   15466    90896   334707    941100 ...
  8 | 1  4807  137085  1159587  5579961  19354687 ...
  9 | 1 24739 1260545 15369761 96589350 413533260 ...
  ...
		

Crossrefs

Columns k=1..4 are A000012, A296532, A361237, A361238.
Row n=3 is A042948.

Programs

  • PARI
    \\ here u is Fuss-Catalan sequence with p = 2*k-1.
    u(n,k,r) = {r*binomial(n*(2*k-1) + r, n)/(n*(2*k-1) + r)}
    T(n,k) = if(n==0, 1, u(n, k, 1)/((k-1)*n+1) + sumdiv(gcd(k,n-1), d, if(d>1, eulerphi(d)*u((n-1)/d, k, 2*k/d)/k)))

Formula

T(0,k) = T(1,k) = T(2,k) = 1.

A091144 a(n) = binomial(n^2, n)/(1+(n-1)*n).

Original entry on oeis.org

1, 1, 2, 12, 140, 2530, 62832, 1997688, 77652024, 3573805950, 190223180840, 11502251937176, 779092434772236, 58448142042957576, 4811642166029230560, 431306008583779517040, 41820546066482630185200
Offset: 0

Views

Author

Paul Barry, Dec 22 2003

Keywords

Comments

Diagonal of array T(n,k) = binomial(kn,n)/(1+(k-1)n).
Number of paths up and left from (0,0) to (n^2-n,n) where x/y <= n-1 for all intermediate points. - Henry Bottomley, Dec 25 2003
Empirical: In the ring of symmetric functions over the fraction field Q(q, t), letting s(1^n) denote the Schur function indexed by (1^n), a(n) is equal to the coefficient of s(n) in nabla^(n)s(1^n) with q=t=1, where nabla denotes the "nabla operator" on symmetric functions, and s(n) denotes the Schur function indexed by the integer partition (n) of n. - John M. Campbell, Apr 06 2018

Crossrefs

Programs

  • GAP
    List([0..20],n->Binomial(n^2,n)/(1+(n-1)*n)); # Muniru A Asiru, Apr 08 2018
  • Magma
    [Binomial(n^2, n)/(1+(n-1)*n): n in [0..20]]; // Vincenzo Librandi, Apr 07 2018
    
  • Maple
    A091144 := proc(n)
        binomial(n^2,n)/(1+n*(n-1)) ;
    end proc: # R. J. Mathar, Feb 14 2015
  • Mathematica
    Table[Binomial[n^2, n] / (n (n - 1) + 1), {n, 0, 20}] (* Vincenzo Librandi, Apr 07 2018 *)
  • PARI
    a(n) = binomial(n^2, n)/(n*(n-1)+1); \\ Altug Alkan, Apr 06 2018
    

Formula

From Henry Bottomley, Dec 25 2003: (Start)
a(n) = A014062(n)/A002061(n);
a(n) = A062993(n-2, n);
a(n) = A070914(n, n-1);
a(n) = A071201(n, n^2-n);
a(n) = A071201(n, n^2-n+1);
a(n) = A071202(n, n^2-n+1). (End)

A370060 Array read by antidiagonals: T(n,k) is the number of achiral dissections of a polygon into n k-gons by nonintersecting diagonals rooted at a cell, n >= 1, k >= 3.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 3, 2, 1, 1, 2, 4, 2, 1, 1, 4, 4, 12, 5, 1, 1, 3, 6, 9, 18, 5, 1, 1, 5, 6, 26, 22, 55, 14, 1, 1, 4, 8, 21, 45, 52, 88, 14, 1, 1, 6, 8, 45, 51, 204, 140, 273, 42, 1, 1, 5, 10, 38, 84, 190, 380, 340, 455, 42, 1, 1, 7, 10, 69, 92, 500, 506, 1771, 969, 1428, 132
Offset: 1

Views

Author

Andrew Howroyd, Feb 08 2024

Keywords

Comments

The polygon prior to dissection will have n*(k-2)+2 sides.

Examples

			Array begins:
=============================================
n\k|  3   4   5    6    7    8    9    10 ...
---+-----------------------------------------
1  |  1   1   1    1    1    1    1     1 ...
2  |  1   1   1    1    1    1    1     1 ...
3  |  1   3   2    4    3    5    4     6 ...
4  |  2   4   4    6    6    8    8    10 ...
5  |  2  12   9   26   21   45   38    69 ...
6  |  5  18  22   45   51   84   92   135 ...
7  |  5  55  52  204  190  500  468   992 ...
8  | 14  88 140  380  506 1008 1240  2100 ...
9  | 14 273 340 1771 1950 6200 6545 15990 ...
  ...
		

Crossrefs

Columns k=3..6 are A208355(n-1), A124817(n-1), A369472, A370061.
Cf. A070914 (rooted), A295222 (oriented), A295259 (unoriented), A369929, A370062 (achiral unrooted).

Programs

  • PARI
    \\ here u is Fuss-Catalan sequence with p = k-1.
    u(n, k, r) = {r*binomial((k - 1)*n + r, n)/((k - 1)*n + r)}
    T(n, k) = {if(k%2, if(n%2, u((n-1)/2, k, (k-1)/2), u(n/2-1, k, (k-1))), if(n%2, u((n-1)/2, k, k/2+1), u(n/2-1, k, k)) )}
    for(n=1, 9, for(k=3, 10, print1(T(n, k), ", ")); print);

Formula

T(n,k) = 2*A295259(n,k) - A295222(n,k).
T(n,2*k+1) = A370062(n,2*k+1).

A113206 Triangle read by rows of generalized Catalan numbers.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 2, 0, 1, 1, 0, 3, 5, 3, 0, 1, 1, 0, 4, 12, 14, 12, 4, 0, 1, 1, 0, 5, 22, 55, 42, 55, 22, 5, 0, 1, 1, 0, 6, 35, 140, 273, 132, 273, 140, 35, 6, 0, 1, 1, 0, 7, 51, 285, 969, 1428, 429, 1428, 969, 285, 51, 7, 0, 1, 1, 0, 8, 70, 506, 2530, 7084, 7752, 1430, 7752, 7084
Offset: 0

Views

Author

N. J. A. Sloane, Jan 07 2006

Keywords

Comments

A dual to Pascal's triangle. Row n has 2n+1 entries.

Examples

			.............1
...........1.0.1
.........1.0.2.0.1
.......1.0.3.5.3.0.1
....1.0.4.12.14.12.4.0.1
.1.0.5.22.55.42.55.22.5.0.1
		

Crossrefs

Programs

  • Maple
    A070914 := proc(n,k) binomial(n*(k+1),n)/(n*k+1) ; end proc:
    A113206 := proc(n,k) if k = 2 or k = 2*n-2 then 0 ; else A070914(n-abs(n-k)-1,abs(n-k)+1) ; fi ; end proc:
    for n from 0 to 10 do for k from 1 to 2*n-1 do printf("%d ",A113206(n,k)) ; od: od: # R. J. Mathar, Feb 08 2008
  • Mathematica
    A070914[n_, k_] := Binomial[n*(k + 1), n]/(n*k + 1);
    A113206[n_, k_] := If[k == 2 || k == 2*n - 2, 0, A070914[n - Abs[n-k] - 1, Abs[n-k] + 1]];
    Table[A113206[n, k], {n, 0, 10}, {k, 1, 2*n - 1}] // Flatten (* Jean-François Alcover, Nov 28 2017, after R. J. Mathar *)

Formula

T(n,k) = A070914(n-|n-k|-1,|n-k|+1) if 3<=k<=2n-3 . - R. J. Mathar, Feb 08 2008

A255918 Array a(n,m) read by descending antidiagonals giving the number of intervals in a generalized Tamari lattice of m-ballot paths of size n.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 6, 13, 1, 1, 10, 58, 68, 1, 1, 15, 170, 703, 399, 1, 1, 21, 395, 3685, 9729, 2530, 1, 1, 28, 791, 13390, 91881, 146916, 16965, 1, 1, 36, 1428, 38591, 524256, 2509584, 2359968, 118668, 1, 1, 45, 2388, 94738, 2180262, 22533126
Offset: 1

Views

Author

Jean-François Alcover, Mar 11 2015

Keywords

Comments

This array occurs in counting the degeneracies in the supersymmetric ground states of the Kronecker model of quiver quantum mechanics. See Cordova and Shao, 1.4. - Peter Bala, Oct 29 2017
In mathematical terms, this corresponds to the homology of some moduli spaces of semi-stable representations of the Kronecker quiver K_m with dimension vector (n,n+1). F. Chapoton, Jun 09 2021

Examples

			Array begins:
1,   1,    1,     1,      1,       1,       1,        1,        1, ...
1,   3,    6,    10,     15,      21,      28,       36,       45, ...
1,  13,   58,   170,    395,     791,    1428,     2388,     3765, ...
1,  68,  703,  3685,  13390,   38591,   94738,   206718,   412095, ...
1, 399, 9729, 91881, 524256, 2180262, 7291550, 20787390, 52450587, ...
...
2nd row is A000217 (triangular numbers);
3rd row is A103220;
4th row is not in the OEIS;
2nd column is A000260 (number of intervals in the usual Tamari lattice of size n);
3rd column is not in the OEIS.
		

Crossrefs

Cf. A000217, A000260, A070914 (generalized Catalan numbers giving the number of paths), A103220.

Programs

  • Mathematica
    a[n_, m_] := ((m + 1)/(n*(m*n + 1)))*Binomial[(m + 1)^2*n + m, n - 1]; Table[a[n - m, m], {n, 1, 12}, {m, n - 1, 0, -1}] // Flatten
  • Sage
    def a(n, m):
        return (m + 1) * binomial((m + 1)**2 * n + m, n - 1) // (n*(m*n + 1)) # F. Chapoton, Mar 24 2021

Formula

a(n,m) = ((m + 1)/(n*(m*n + 1)))*binomial((m + 1)^2*n + m, n - 1).

A137211 Generalized or s-Catalan numbers.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 1, 5, 12, 22, 1, 14, 55, 140, 285, 1, 42, 273, 969, 2530, 5481, 1, 132, 1428, 7084, 23751, 62832, 141778, 1, 429, 7752, 53820, 231880, 749398, 1997688, 4638348, 1, 1430, 43263, 420732, 2330445, 9203634, 28989675, 77652024
Offset: 1

Views

Author

Roger L. Bagula, Mar 05 2008

Keywords

Comments

From R. J. Mathar, May 04 2008: (Start)
This is a triangular section of Stanica's array of s-Catalan numbers, with rows A000108, A001764, A002293-A002296, A007556, A062994, A059968,... read along diagonals in A062993 and A070914:
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, ...
1, 1, 3, 12, 55, 273, 1428, 7752, 43263, 246675, 1430715, ...
1, 1, 4, 22, 140, 969, 7084, 53820, 420732, 3362260, 27343888, ...
1, 1, 5, 35, 285, 2530, 23751, 231880, 2330445, 23950355, 250543370, ...
1, 1, 6, 51, 506, 5481, 62832, 749398, 9203634, 115607310, 1478314266, ...
1, 1, 7, 70, 819, 10472, 141778, 1997688, 28989675, 430321633, 6503352856, ...
1, 1, 8, 92, 1240, 18278, 285384, 4638348, 77652024, 1329890705, 23190029720, ...
1, 1, 9, 117, 1785, 29799, 527085, 9706503, 184138713, 3573805950, 70625252863, ...
1, 1, 10, 145, 2470, 46060, 910252, 18730855, 397089550, 8612835715, 190223180840, ...
(End)
The Fuss-Catalan numbers are Cat(d,k)= [1/(k*(d-1)+1)]*binomial(k*d,k) and enumerate the number of (d+1)-gon partitions of a (k*(d-1)+2)-gon (cf. Whieldon and Schuetz link for this interpretation and others), so the (k+1)-th column of Stanica's array enumerates the number of (n+1)-gon partitions of a (k*(n-1)+2)-gon. Cf. A000326 (k=3), A100157 (k=4) and A234043 (k=5). - Tom Copeland, Oct 05 2014

Examples

			{1},
{1, 1},
{1, 2, 3},
{1, 5, 12, 22},
{1, 14, 55, 140, 285},
{1, 42, 273, 969, 2530, 5481},
{1, 132, 1428, 7084, 23751, 62832, 141778},
{1, 429, 7752, 53820, 231880, 749398, 1997688, 4638348}
		

Programs

  • Mathematica
    t[n_, m_] := Binomial[m*n, n]/((m - 1)*n + 1); a = Table[Table[t[n, m], {m, 1, n + 1}], {n, 0, 10}]; Flatten[a]

Formula

T(n,m) = binomial(m*n,n)/((m-1)*n+1).

Extensions

Edited by N. J. A. Sloane, May 16 2008
Previous Showing 11-18 of 18 results.