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).

A336247 a(n) = (n!)^n * Sum_{k=0..n} 1 / (k!)^n.

Original entry on oeis.org

1, 2, 9, 460, 684545, 50547203126, 280807908057046657, 165858480204085842350156792, 13997217669604247492958380810030809089, 218434494471443385260764665498960241287478619115850, 792268399795067334328715213043856435592857850955707257780000000001
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 14 2020

Keywords

Crossrefs

Main diagonal of A343863.

Programs

  • Mathematica
    Table[(n!)^n Sum[1/(k!)^n, {k, 0, n}], {n, 0, 10}]
  • PARI
    a(n) = (n!)^n * sum(k=0, n, 1/(k!)^n); \\ Michel Marcus, Jul 14 2020

A336250 a(n) = (n!)^n * Sum_{k=1..n} (-1)^(k+1) / k^n.

Original entry on oeis.org

0, 1, 3, 197, 313840, 24191662624, 137300308036448256, 81994640912971156525105152, 6958651785463110878359050928999366656, 108902755985567407887534498777329973193771818418176, 395560567918154447056086270973712023435510589158871531520000000000
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 14 2020

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n!)^n Sum[(-1)^(k + 1)/k^n, {k, 1, n}], {n, 0, 10}]
    Table[(n!)^n SeriesCoefficient[-PolyLog[n, -x]/(1 - x), {x, 0, n}], {n, 0, 10}]
  • PARI
    a(n) = (n!)^n * sum(k=1, n, (-1)^(k+1) / k^n); \\ Michel Marcus, Jul 14 2020

Formula

a(n) = (n!)^n * [x^n] -polylog(n,-x) / (1 - x).
Showing 1-3 of 3 results.