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.

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A326476 A(n, k) = (m*k)! [x^k] MittagLefflerE(m, x)^n, for m = 2, n >= 0, k >= 0; square array read by descending antidiagonals.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 8, 3, 1, 0, 1, 32, 21, 4, 1, 0, 1, 128, 183, 40, 5, 1, 0, 1, 512, 1641, 544, 65, 6, 1, 0, 1, 2048, 14763, 8320, 1205, 96, 7, 1, 0, 1, 8192, 132861, 131584, 26465, 2256, 133, 8, 1, 0, 1, 32768, 1195743, 2099200, 628805, 64896, 3787, 176, 9, 1
Offset: 0

Views

Author

Peter Luschny, Jul 08 2019

Keywords

Examples

			Array starts:
  [0] 1, 0,   0,    0,      0,        0,          0,            0, ... A000007
  [1] 1, 1,   1,    1,      1,        1,          1,            1, ... A000012
  [2] 1, 2,   8,   32,    128,      512,       2048,         8192, ... A081294
  [3] 1, 3,  21,  183,   1641,    14763,     132861,      1195743, ... A054879
  [4] 1, 4,  40,  544,   8320,   131584,    2099200,     33562624, ... A092812
  [5] 1, 5,  65, 1205,  26465,   628805,   15424865,    382964405, ... A121822
  [6] 1, 6,  96, 2256,  64896,  2086656,   71172096,   2499219456, ...
  [7] 1, 7, 133, 3787, 134953,  5501167,  243147373,  11266376947, ...
  [8] 1, 8, 176, 5888, 250496, 12397568,  676591616,  39316226048, ...
  [9] 1, 9, 225, 8649, 427905, 24943689, 1624354785, 114066126729, ...
        A000567,
Seen as a triangle:
  1;
  0, 1;
  0, 1,    1;
  0, 1,    2,      1;
  0, 1,    8,      3,      1;
  0, 1,   32,     21,      4,     1;
  0, 1,  128,    183,     40,     5,    1;
  0, 1,  512,   1641,    544,    65,    6,   1;
  0, 1, 2048,  14763,   8320,  1205,   96,   7, 1;
  0, 1, 8192, 132861, 131584, 26465, 2256, 133, 8, 1;
		

Crossrefs

Rows n=0..5 give A000007, A000012, A081294, A054879, A092812, A121822.
Columns include: A000567.
Main diagonal gives A381459.
Variant: A286899.
Cf. A326474 (m=3, p>=0), A326475 (m=3, p<=0), A326327 (m=2, p<=0), this sequence (m=2, p>=0).

Programs

  • Mathematica
    (* The function MLPower is defined in A326327. *)
    For[n = 0, n < 8, n++, Print[MLPower[2, n, 8]]]
  • PARI
    a(n, k) = (2*k)!*polcoef(cosh(x+x*O(x^(2*k)))^n, 2*k); \\ Seiichi Manyama, May 11 2025
  • Sage
    # uses[MLPower from A326327]
    for n in (0..6): print(MLPower(2, n, 9))
    

Formula

A(n,k) = (2*k)! * [x^(2*k)] cosh(x)^n. - Seiichi Manyama, May 11 2025

A383837 a(n) = (3*n)!/n! * [x^(3*n)] sinh(x)^n.

Original entry on oeis.org

1, 1, 16, 820, 87296, 15857205, 4390088704, 1721255653656, 907673633095680, 619593964021650475, 531571294549842067456, 559896149105493602658256, 710322778732936488128872448, 1068386732538408106621063668220, 1879866814874817967233600382304256
Offset: 0

Views

Author

Seiichi Manyama, May 11 2025

Keywords

Crossrefs

Main diagonal of A381512.

Programs

  • Mathematica
    Join[{1}, Table[Sum[(-1)^k * (n-2*k)^(3*n) * Binomial[n, k] / (2^n*n!), {k,0,n}],{n,1,20}]] (* Vaclav Kotesovec, May 13 2025 *)
  • PARI
    a(n) = sum(k=0, n, (-1)^k*(n-2*k)^(3*n)*binomial(n, k))/(2^n*n!);

Formula

a(n) = [x^n] 1/Product_{k=0..floor(n/2)} (1 - (n-2*k)^2*x).
a(n) = (1/(2^n*n!)) * Sum_{k=0..n} (-1)^k * (n-2*k)^(3*n) * binomial(n,k).
a(n) ~ c * d^n * n^(2*n - 1/2), where d = 1.35572032955623014748562257137412853926900571707993382361... and c = 0.81034327454108346293530087910356437429774959841653144433... - Vaclav Kotesovec, May 13 2025
In closed form, a(n) ~ r^(r*n) * (1 + 2*r)^(3*n+1) * exp(n) * n^(2*n - 1/2) / (sqrt(Pi*(1 - 8*r - 8*r^2)) * 2^(n - 1/2) * (1+r)^((1+r)*n)), where r = 0.002562299585216598238663221142585901101711497682846... is the positive real root of the equation exp(2*arctanh(1 + 2*r) - 6/(1 + 2*r)) = -1. - Vaclav Kotesovec, May 17 2025
Showing 1-2 of 2 results.