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 1-3 of 3 results.

A291556 Square array A(n,k), n>=0, k>=0, read by antidiagonals: A(n,k) = (n!)^k * Sum_{i=1..n} 1/i^k.

Original entry on oeis.org

0, 0, 1, 0, 1, 2, 0, 1, 3, 3, 0, 1, 5, 11, 4, 0, 1, 9, 49, 50, 5, 0, 1, 17, 251, 820, 274, 6, 0, 1, 33, 1393, 16280, 21076, 1764, 7, 0, 1, 65, 8051, 357904, 2048824, 773136, 13068, 8, 0, 1, 129, 47449, 8252000, 224021776, 444273984, 38402064, 109584, 9
Offset: 0

Views

Author

Seiichi Manyama, Aug 26 2017

Keywords

Examples

			Square array begins:
   0,  0,   0,     0,      0, ...
   1,  1,   1,     1,      1, ...
   2,  3,   5,     9,     17, ...
   3, 11,  49,   251,   1393, ...
   4, 50, 820, 16280, 357904, ...
		

Crossrefs

Rows n=0-3 give: A000004, A000012, A000051, A074528.
Main diagonal gives A060943.

Programs

  • Maple
    A:= (n, k)-> n!^k * add(1/i^k, i=1..n):
    seq(seq(A(n, d-n), n=0..d), d=0..10);  # Alois P. Heinz, Aug 26 2017
  • Mathematica
    A[0, ] = 0; A[1, ] = 1; A[n_, k_] := A[n, k] = ((n-1)^k + n^k) A[n-1, k] - (n-1)^(2k) A[n-2, k];
    Table[A[n-k, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, May 11 2019 *)

Formula

A(0, k) = 0, A(1, k) = 1, A(n+1, k) = (n^k+(n+1)^k)*A(n, k) - n^(2*k)*A(n-1, k).

A291456 a(n) = (n!)^6 * Sum_{i=1..n} 1/i^6.

Original entry on oeis.org

0, 1, 65, 47449, 194397760, 3037656102976, 141727869124448256, 16674281388691716870144, 4371079210518164503303028736, 2322975003299339366419974718488576, 2322977286679362958150790503464960000000
Offset: 0

Views

Author

Seiichi Manyama, Aug 24 2017

Keywords

Crossrefs

Column k=6 of A291556.
Cf. A000254 (k=1), A001819 (k=2), A066989 (k=3), A203229 (k=4), A099827 (k=5).

Programs

  • Mathematica
    Table[(n!)^6 * Sum[1/i^6, {i, 1, n}], {n, 0, 15}] (* Vaclav Kotesovec, Aug 27 2017 *)

Formula

a(0) = 0, a(1) = 1, a(n+1) = (n^6 + (n+1)^6)*a(n) - n^12*a(n-1) for n > 0.
a(n) ~ 8 * Pi^9 * n^(6*n+3) / (945 * exp(6*n)). - Vaclav Kotesovec, Aug 27 2017
a(n) = (n!)^6 * A103345(n)/A103346(n). - Petros Hadjicostas, May 10 2020
Sum_{n>=0} a(n) * x^n / (n!)^6 = polylog(6,x) / (1 - x). - Ilya Gutkovskiy, Jul 15 2020

A291586 a(n) = ((2n-1)!!)^4 * Sum_{i=1..n} 1/(2*i-1)^4.

Original entry on oeis.org

0, 1, 82, 51331, 123296356, 809068942341, 11846375878465206, 338356017569383549191, 17129606870671774862445000, 1430698777932227525446706735625, 186451505481090040331197201556276250, 36261458995575361475673937929555130516875
Offset: 0

Views

Author

Seiichi Manyama, Aug 27 2017

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(2*n-1)!!^4 * Sum[1/(2*i-1)^4, {i, 1, n}], {n, 0, 15}] (* Vaclav Kotesovec, Aug 27 2017 *)

Formula

a(0) = 0, a(1) = 1, a(n+1) = ((2*n-1)^4+(2*n+1)^4)*a(n) - (2*n-1)^8*a(n-1) for n > 0.
a(n) ~ Pi^4 * 2^(4*n-3) * n^(4*n) / (3*exp(4*n)). - Vaclav Kotesovec, Aug 27 2017
Showing 1-3 of 3 results.