A112914 Column 3 of triangle A112911.

1, 4, 24, 176, 1492, 14220, 149812, 1724760, 21519108, 289101836, 4160750192, 63873461064, 1042061108096, 18008563271632, 328712410879632, 6320649807989400, 127724091041379492, 2706397280528315148

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Formula

a(n) = Sum_{k=0..n-1} (n-k+3)*A088716(k)*a(n-k-1) for n>0 with a(0)=1.

Prog

(PARI) {a(n)=local(A=Mat(1), B); for(m=2, n+4, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, B[i, j]=-j*(A^-1)[i-j, 1]); )); A=B); return((A^-1)[n+4, 4])}

Crossrefs

Cf. A112911 (triangle), A088716 (column 0), A112912 (column 1), A112913 (column 2).

Sequence in context: A103334 A156017 A000309 * A308543 A007846 A337507

Adjacent sequences: A112911 A112912 A112913 * A112915 A112916 A112917

Keyword

nonn

Author

Paul D. Hanna, Oct 06 2005

Status

approved