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.

A368585 a(n) = n! * Sum_{k=0..n} (-1)^(n-k) * binomial(k+2,3) / k!.

Original entry on oeis.org

0, 1, 2, 4, 4, 15, -34, 322, -2456, 22269, -222470, 2447456, -29369108, 381798859, -5345183466, 80177752670, -1282844041904, 21808348713337, -392550276838926, 7458455259940924, -149169105198816940, 3132551209175157511, -68916126601853463218
Offset: 0

Views

Author

Seiichi Manyama, Dec 31 2023

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); concat(0, Vec(serlaplace(x*sum(k=0, 2, binomial(2, k)*x^k/(k+1)!)*exp(x)/(1+x))))

Formula

a(0) = 0; a(n) = -n*a(n-1) + binomial(n+2,3).
E.g.f.: x * (1+x+x^2/6) * exp(x) / (1+x).

A368586 a(n) = n! * Sum_{k=0..n} (-1)^(n-k) * binomial(k+3,4) / k!.

Original entry on oeis.org

0, 1, 3, 6, 11, 15, 36, -42, 666, -5499, 55705, -611754, 7342413, -95449549, 1336296066, -20044437930, 320711010756, -5452087178007, 98137569210111, -1864613814984794, 37292276299704735, -783137802293788809, 17229031650463366448, -396267727960657413354
Offset: 0

Views

Author

Seiichi Manyama, Dec 31 2023

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); concat(0, Vec(serlaplace(x*sum(k=0, 3, binomial(3, k)*x^k/(k+1)!)*exp(x)/(1+x))))

Formula

a(0) = 0; a(n) = -n*a(n-1) + binomial(n+3,4).
E.g.f.: x * (1+3*x/2+x^2/2+x^3/24) * exp(x) / (1+x).

A368718 a(n) = n! * Sum_{k=0..n} (-1)^(n-k) * k^5 / k!.

Original entry on oeis.org

0, 1, 30, 153, 412, 1065, 1386, 7105, -24072, 275697, -2656970, 29387721, -352403820, 4581620953, -64142155518, 962133092145, -15394128425744, 261700184657505, -4710603321945522, 89501463119441017, -1790029262385620340, 37590614510102111241
Offset: 0

Views

Author

Seiichi Manyama, Jan 04 2024

Keywords

Comments

In general, for m >=0, Sum_{k=0..n} (-1)^(n-k) * k^m / k! ~ A000587(m) * (-1)^n * exp(-1). - Vaclav Kotesovec, Jul 18 2025

Crossrefs

Column k=5 of A368724.

Programs

  • Maple
    f:= proc(n) option remember;
      - n*procname(n-1)+n^5
    end proc:
    f(0):= 0:
    seq(f(i),i=0..21); # Robert Israel, May 13 2025
  • Mathematica
    Table[-5*n + 3*n^3 + n^4 - 2*(-1)^n*n*Subfactorial[n-1], {n, 0, 20}] (* Vaclav Kotesovec, Jul 18 2025 *)
  • PARI
    my(N=30, x='x+O('x^N)); concat(0, Vec(serlaplace(sum(k=0, 5, stirling(5, k, 2)*x^k)*exp(x)/(1+x))))

Formula

a(0) = 0; a(n) = -n*a(n-1) + n^5.
E.g.f.: B_5(x) * exp(x) / (1+x), where B_n(x) = Bell polynomials.
a(n) ~ -2*(-1)^n * exp(-1) * n!. - Vaclav Kotesovec, Jul 18 2025
Showing 1-3 of 3 results.