A112913 Column 2 of triangle A112911.

1, 3, 15, 96, 729, 6327, 61380, 655944, 7642557, 96338925, 1306003803, 18947038404, 292956751236, 4810423131828, 83620543389804, 1534493081643552, 29649997606132197, 601828286370137865, 12804746026265284149

Offset: 0

Author

Paul D. Hanna, Oct 06 2005

Keywords

• nonn

Crossrefs

Cf. A112911 (triangle), A088716 (column 0), A112912 (column 1), A112914 (column 3).

Programs

PARI

{a(n)=local(A=Mat(1),B);for(m=2,n+3,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+3,3])}

Formula

a(n) = Sum_{k=0..n-1} (n-k+2)*A088716(k)*a(n-k-1) for n>0 with a(0)=1.