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.

Showing 1-6 of 6 results.

A366137 Main diagonal of A365673.

Original entry on oeis.org

1, 1, 3, 34, 1385, 151416, 34988647, 14652451360, 10043767063521, 10488938037348736, 15823297170233169371, 33093543421485325857024, 92866643063435821361785225, 340452463858281665211769947136, 1594758692956372710911812262365695, 9367635873493885183992990317902544896
Offset: 0

Views

Author

Peter Luschny, Sep 30 2023

Keywords

Comments

See the formulas in A365673.

Crossrefs

Cf. A365673.

Programs

  • Maple
    # Using function T from A365673.
    seq(T(n, n, n), n = 0..15);

A366149 Triangle read by rows. T(n, k) = A000566(n - k + 1) * T(n, k - 1) + T(n - 1, k) for 0 < k < n. T(n, 0) = 1 and T(n, n) = T(n, n - 1) if n > 0.

Original entry on oeis.org

1, 1, 1, 1, 8, 8, 1, 26, 190, 190, 1, 60, 1270, 9080, 9080, 1, 115, 5180, 102320, 725320, 725320, 1, 196, 15960, 644960, 12334600, 87067520, 87067520, 1, 308, 40908, 2894900, 110761200, 2080769120, 14652451360, 14652451360
Offset: 0

Views

Author

Peter Luschny, Oct 01 2023

Keywords

Comments

This a weighted generalized Catalan triangle (A365673) with the heptagonal numbers as weights.

Examples

			Triangle T(n, k) starts:
[0] 1;
[1] 1,   1;
[2] 1,   8,     8;
[3] 1,  26,   190,     190;
[4] 1,  60,  1270,    9080,      9080;
[5] 1, 115,  5180,  102320,    725320,     725320;
[6] 1, 196, 15960,  644960,  12334600,   87067520,    87067520;
[7] 1, 308, 40908, 2894900, 110761200, 2080769120, 14652451360, 14652451360;
		

Crossrefs

Cf. A000566, A366150 (main diagonal), A365673 (general case).

Programs

  • Maple
    T := proc(n, k) option remember;
    if k = 0 then 1 else if k = n then T(n, k-1) else
    (((5*k - 5*n - 2)*(k - n - 1))/2) * T(n, k - 1) + T(n - 1, k) fi fi end:
    seq(seq(T(n, k), k = 0..n), n = 0..8);
  • Mathematica
    A366149[n_, k_] := A366149[n, k] = Which[k==0, 1, k==n, A366149[n, k-1], True, PolygonalNumber[7, n-k+1] A366149[n, k-1] + A366149[n-1, k]];
    Table[A366149[n, k], {n,0,10}, {k,0,n}] (* Paolo Xausa, Jan 01 2024 *)

A365672 Triangle read by rows. T(n, k) = 1 if k = 0, equals T(n, k-1) if k = n, and otherwise is (n - k + 1) * (2 * (n - k) + 1) * T(n, k - 1) + T(n - 1, k).

Original entry on oeis.org

1, 1, 1, 1, 7, 7, 1, 22, 139, 139, 1, 50, 889, 5473, 5473, 1, 95, 3549, 58708, 357721, 357721, 1, 161, 10794, 360940, 5771821, 34988647, 34988647, 1, 252, 27426, 1595110, 50434901, 791512162, 4784061619, 4784061619
Offset: 0

Views

Author

Peter Luschny, Sep 29 2023

Keywords

Comments

This triangle is described by Peter Bala (see link).
This a weighted generalized Catalan triangle (A365673) with the hexagonal numbers as weights.

Examples

			Triangle T(n, k) starts:
[0] 1;
[1] 1,   1;
[2] 1,   7,     7;
[3] 1,  22,   139,     139;
[4] 1,  50,   889,    5473,     5473;
[5] 1,  95,  3549,   58708,   357721,    357721;
[6] 1, 161, 10794,  360940,  5771821,  34988647,   34988647;
[7] 1, 252, 27426, 1595110, 50434901, 791512162, 4784061619, 4784061619;
		

Crossrefs

Cf. A000384, A126156 (main diagonal), A365673 (general case).

Programs

  • Maple
    T := proc(n, k) option remember; if k = 0 then 1 else if k = n then T(n, k-1) else (n - k + 1) * (2 * (n - k) + 1) * T(n, k - 1) + T(n - 1, k) fi fi end:

A366150 a(n) = A366149(n, n).

Original entry on oeis.org

1, 1, 8, 190, 9080, 725320, 87067520, 14652451360, 3291452374400, 951504315644800, 344097665398707200, 152191547632887731200, 80821740082953347993600, 50749489515964112842240000, 37193794460546391363092480000, 31464706192542487393274091520000
Offset: 0

Views

Author

Peter Luschny, Oct 01 2023

Keywords

Comments

This a weighted generalized Catalan sequence (A365673) with the heptagonal numbers as weights.

Crossrefs

Programs

A365674 Triangle read by rows. T(n, k) = ((n - k + 1)*(n - k + 2)/2) * T(n, k - 1) + T(n - 1, k) for 0 < k < n, T(n, 0) = 1 and T(n, n) = T(n, n - 1) for n > 0.

Original entry on oeis.org

1, 1, 1, 1, 4, 4, 1, 10, 34, 34, 1, 20, 154, 496, 496, 1, 35, 504, 3520, 11056, 11056, 1, 56, 1344, 16960, 112816, 349504, 349504, 1, 84, 3108, 63580, 748616, 4841200, 14873104, 14873104, 1, 120, 6468, 199408, 3739736, 42238560, 268304464, 819786496, 819786496
Offset: 0

Views

Author

Peter Luschny, Sep 30 2023

Keywords

Comments

This triangle is associated to the case n = 3 of A365673 and has as weight function the triangular numbers A000217. The numbers on its main diagonal are the reduced tangent numbers A002105. For details see A365673.

Examples

			[0] 1;
[1] 1,  1;
[2] 1,  4,    4;
[3] 1, 10,   34,    34;
[4] 1, 20,  154,   496,    496;
[5] 1, 35,  504,  3520,  11056,   11056;
[6] 1, 56, 1344, 16960, 112816,  349504,   349504;
[7] 1, 84, 3108, 63580, 748616, 4841200, 14873104, 14873104;
		

Crossrefs

Cf. A002105 (main diagonal), A365673 (case n=3), A000217 (weight).

Programs

  • Maple
    T := proc(n, k) option remember; if k = 0 then 1 else if k = n then T(n, k - 1) else ((n - k + 1)*(n - k + 2)/2) * T( n, k - 1) + T( n - 1, k) fi fi end:
    seq(print(seq(T(n, k), k = 0..n)), n = 0..8);

A366138 Triangle read by rows. T(n, k) = A000326(n - k + 1) * T(n, k - 1) + T(n - 1, k) for 0 < k < n. T(n, 0) = 1 and T(n, n) = T(n, n - 1) if n > 0.

Original entry on oeis.org

1, 1, 1, 1, 6, 6, 1, 18, 96, 96, 1, 40, 576, 2976, 2976, 1, 75, 2226, 29688, 151416, 151416, 1, 126, 6636, 175680, 2259576, 11449296, 11449296, 1, 196, 16632, 757800, 18931176, 238623408, 1204566336, 1204566336
Offset: 0

Views

Author

Peter Luschny, Oct 01 2023

Keywords

Comments

This a weighted generalized Catalan triangle (A365673) with the pentagonal numbers as weights.

Examples

			Triangle T(n, k) starts:
[0] 1;
[1] 1,   1;
[2] 1,   6,     6;
[3] 1,  18,    96,     96;
[4] 1,  40,   576,   2976,     2976;
[5] 1,  75,  2226,  29688,   151416,    151416;
[6] 1, 126,  6636, 175680,  2259576,  11449296,   11449296;
[7] 1, 196, 16632, 757800, 18931176, 238623408, 1204566336, 1204566336;
		

Crossrefs

Cf. A000326, A126151 (main diagonal), A365673.

Programs

  • Maple
    T := proc(n, k) option remember; if k = 0 then 1 else if k = n then T(n, k-1)
    else (((n - k + 1)*(3*n - 3*k + 2))/2) * T(n, k - 1) + T(n - 1, k) fi fi end:
    seq(seq(T(n, k), k = 0..n), n = 0..8);
Showing 1-6 of 6 results.