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.

A269957 Triangle read by rows, T(n,k) = Sum_{j=k..n} A269940(n,j)*A269939(j,k), for n>=0 and 0<=k<=n.

Original entry on oeis.org

1, 0, 1, 0, 5, 9, 0, 41, 210, 225, 0, 469, 5115, 14175, 11025, 0, 6889, 142492, 763350, 1455300, 893025, 0, 123605, 4566149, 41943090, 146522250, 212837625, 108056025, 0, 2620169, 166939742, 2462128095, 13973628900, 35936814375, 42141849750, 18261468225
Offset: 0

Views

Author

Peter Luschny, Mar 27 2016

Keywords

Examples

			Triangle starts:
[1]
[0, 1]
[0, 5, 9]
[0, 41, 210, 225]
[0, 469, 5115, 14175, 11025]
[0, 6889, 142492, 763350, 1455300, 893025]
		

Crossrefs

Programs

  • Sage
    F = lambda n,k,f: sum((-1)^(m+k)*binomial(n+k,n+m)*f(n+m,m) for m in (0..k))
    T = lambda n,k: sum(F(n, j, stirling_number1)*F(j, k, stirling_number2) for j in (k..n))
    for n in (0..6): print([T(n, k) for k in (0..n)])

Formula

T(n,n) = A001818(n).
T(n,1) = A032188(n+1) for n>=1.