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.

A354610 Expansion of e.g.f. exp(f(x) - 1) where f(x) = (1 - x)^x = e.g.f. for A007114.

Original entry on oeis.org

1, 0, -2, -3, 16, 90, -84, -2940, -8672, 95256, 956160, -811800, -75724296, -419150160, 4406562720, 78306555600, 89704074240, -9655388184960, -97621097227200, 657339885653760, 23680733504400000, 119677890314505600, -3528587069869276800, -64401874868363598720
Offset: 0

Views

Author

Seiichi Manyama, Jul 08 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp((1-x)^x-1)))
    
  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, j!*sum(k=0, j\2, (-1)^(j-k)*stirling(j-k, k, 1)/(j-k)!)*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A007114(k) * binomial(n-1,k-1) * a(n-k).

A318616 a(n) = n! * [x^n] (1 - x)^(n*x).

Original entry on oeis.org

1, 0, -4, -9, 160, 1350, -14904, -335160, 1796096, 125615448, 204300000, -64591072920, -735003528192, 41673388751280, 1113912529707264, -30043364514345000, -1703374149711298560, 17822402097051182400, 2856178489894627203072, 12394040043610922716800, -5255899207995216384000000
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 30 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Table[n! SeriesCoefficient[(1 - x)^(n x), {x, 0, n}], {n, 0, 20}]
    Join[{1}, Table[n! Sum[(-1)^k n^(n - k) StirlingS1[k, n - k]/k!, {k, n}], {n, 20}]]

Formula

a(n) = n! * [x^n] exp(-n*x*Sum_{k>=1} x^k/k).
a(n) = n! * Sum_{k=0..n} (-1)^k*n^(n-k)*Stirling1(k,n-k)/k!.

A354611 Expansion of e.g.f. 1/(2 - (1 - x)^x).

Original entry on oeis.org

1, 0, -2, -3, 28, 150, -714, -10920, 13392, 1129464, 3694680, -150143400, -1515256104, 22631946480, 525582087408, -2756199995640, -192774443051520, -525316900812480, 75951597634314048, 926307802605928320, -30597152030347651200, -833744424171043728000
Offset: 0

Views

Author

Seiichi Manyama, Jul 08 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(2-(1-x)^x)))
    
  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, j!*sum(k=0, j\2, (-1)^(j-k)*stirling(j-k, k, 1)/(j-k)!)*binomial(i, j)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A007114(k) * binomial(n,k) * a(n-k).
Showing 1-3 of 3 results.