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 1-2 of 2 results.

A350721 a(n) = Sum_{k=0..n} k! * k^(k+n) * Stirling1(n,k).

Original entry on oeis.org

1, 1, 31, 4184, 1495534, 1110325474, 1481505320078, 3225820132807320, 10696978730747904696, 51287741246274865567776, 341442095880058160040860592, 3055472627228313328903357352784, 35788671820468495762774011478900032
Offset: 0

Views

Author

Seiichi Manyama, Feb 03 2022

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := Sum[k! * k^(k+n) * StirlingS1[n, k], {k, 1, n}]; Array[a, 13, 0] (* Amiram Eldar, Feb 03 2022 *)
  • PARI
    a(n) = sum(k=0, n, k!*k^(k+n)*stirling(n, k, 1));
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, (k*log(1+k*x))^k)))

Formula

E.g.f.: Sum_{k>=0} (k * log(1 + k*x))^k.
a(n) ~ exp(-exp(-2)/2) * n! * n^(2*n). - Vaclav Kotesovec, Feb 04 2022

A350719 a(n) = Sum_{k=0..n} k! * 2^k * k^n * Stirling1(n,k).

Original entry on oeis.org

1, 2, 30, 1108, 76372, 8463328, 1375868768, 308440047648, 91189383264864, 34376022491122368, 16093445542120281792, 9160424435706947112576, 6230035512106223752576896, 4989402076922846372194268160, 4647526704475074504983564884992
Offset: 0

Views

Author

Seiichi Manyama, Feb 03 2022

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := Sum[k! * 2^k * k^n * StirlingS1[n, k], {k, 1, n}]; Array[a, 15, 0] (* Amiram Eldar, Feb 03 2022 *)
  • PARI
    a(n) = sum(k=0, n, k!*2^k*k^n*stirling(n, k, 1));
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, (2*log(1+k*x))^k)))

Formula

E.g.f.: Sum_{k>=0} (2 * log(1 + k*x))^k.
Showing 1-2 of 2 results.