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.

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A343900 a(n) = Sum_{k=0..n} (k!)^(k+1) * binomial(n,k).

Original entry on oeis.org

1, 2, 11, 1324, 7967861, 2986023826166, 100306147958903465407, 416336313421816733159702737376, 281633758448076539969292901914477101456489, 39594086612245054028213574779019294652734771094507399786
Offset: 0

Views

Author

Seiichi Manyama, May 03 2021

Keywords

Comments

Binomial transform of (n!)^(n+1).

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[(k!)^(k+1) * Binomial[n, k], {k, 0, n}]; Array[a, 10, 0] (* Amiram Eldar, May 05 2021 *)
  • PARI
    a(n) = sum(k=0, n, k!^(k+1)*binomial(n, k));
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, k!^(k+1)*x^k/(1-x)^(k+1)))
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(x)*sum(k=0, N, (k!*x)^k)))

Formula

G.f.: Sum_{k>=0} (k!)^(k+1) * x^k/(1 - x)^(k+1).
E.g.f.: exp(x) * Sum_{k>=0} (k! * x)^k.

A343928 a(n) = Sum_{k=0..n} (k!)^n * binomial(n,k).

Original entry on oeis.org

1, 2, 7, 244, 337061, 24923091206, 139331988275478727, 82607113404338664216300296, 6984967577834038055008791270166057993, 109110690950275218023122492287310115968068596613130, 395940866518366059877297056617763923418318903997411043997258716171
Offset: 0

Views

Author

Seiichi Manyama, May 04 2021

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[(k!)^n * Binomial[n, k], {k, 0, n} ]; Array[a, 11, 0] (* Amiram Eldar, May 04 2021 *)
  • PARI
    a(n) = sum(k=0, n, k!^n*binomial(n, k));

Formula

a(n) = [x^n] Sum_{k>=0} (k!)^n * x^k/(1 - x)^(k+1).
a(n) = n! * [x^n] exp(x) * Sum_{k>=0} (k!)^(n-1) * x^k.
Showing 1-2 of 2 results.