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

0,2

Links

Table of n, a(n) for n=0..18.

Formula

a(n) = Sum_{k=0..n-1} (n-k+2)*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+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])}

Crossrefs

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

Sequence in context: A354412 A304072 A076301 * A109283 A370210 A079689

Adjacent sequences: A112910 A112911 A112912 * A112914 A112915 A112916

Keyword

nonn

Author

Paul D. Hanna, Oct 06 2005

Status

approved