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.

A347429 a(n) is the alternating sum of the n-th row of A047920.

Original entry on oeis.org

1, 1, 2, 3, 18, 47, 516, 1851, 28502, 128943, 2546352, 13889291, 334552866, 2135390367, 60692391308, 443650121787, 14531752130766, 119684543973551, 4438679955367752, 40666524402277323, 1684291581885909722, 16989963249272202591, 777243725319000331236
Offset: 0

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Author

Alois P. Heinz, Sep 01 2021

Keywords

Crossrefs

Cf. A047920.

Programs

  • Maple
    b:= proc(n, k) option remember;
         `if`(k=0, n!, b(n, k-1)-b(n-1, k-1))
        end:
    a:= n-> add(b(n, k)*(-1)^k, k=0..n):
    seq(a(n), n=0..23);
  • Mathematica
    a[n_] := Sum[(-1)^(j+k)*Binomial[k, j]*(n-j)!, {j, 0, n}, {k, 0, n}];
    Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Jun 04 2022 *)
  • PARI
    row(n) = vector(n+1, k, k--; sum(j=0, n, (-1)^j * binomial(k, j)*(n-j)!)); \\ A047920
    a(n) = my(v=row(n)); sum(k=1, n+1, (-1)^k*row[k]); \\ Michel Marcus, Sep 04 2021

Formula

a(n) = Sum_{k=0..n} (-1)^k * A047920(n,k).