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.

A049378 Row sums of triangle A049353.

Original entry on oeis.org

1, 1, 6, 46, 436, 4956, 65776, 996976, 16957536, 319259296, 6581662336, 147290942976, 3552885191296, 91827536814976, 2530228890080256, 74003737259670016, 2288810287491774976, 74607500831801289216, 2555587654482227055616, 91746983502042106018816
Offset: 0

Views

Author

Keywords

Crossrefs

Column k=5 of A291709.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=0, 1, add(
          binomial(n-1, j-1)*(j+3)!/4!*a(n-j), j=1..n))
        end:
    seq(a(n), n=0..25);  # Alois P. Heinz, Aug 01 2017
  • Mathematica
    a[0] = 1; a[n_] := a[n] = Sum[Binomial[n - 1, j - 1]*(j + 3)!/4!*a[n - j], {j, 1, n}];
    Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Jun 04 2018, after Alois P. Heinz *)

Formula

E.g.f. exp(p(x)) with p(x) := x*(2-x)*(2-2*x+x^2)/(4*(1-x)^4) (E.g.f. first column of A049353).
From Seiichi Manyama, Jan 18 2025: (Start)
a(n) = Sum_{k=0..n} |Stirling1(n,k)| * A004213(k).
a(n) = (1/exp(1/4)) * (-1)^n * n! * Sum_{k>=0} binomial(-4*k,n)/(4^k * k!). (End)

Extensions

a(0)=1 prepended by Alois P. Heinz, Aug 01 2017