A126467 Column 1 of triangle A126465.

1, 1, 6, 105, 3710, 219625, 19545316, 2437990653, 405899413380, 87002614878795, 23351252019790310, 7676367378822833691, 3035533054438876836390, 1422385798272704860377055, 779768824083518449340320720

Offset: 0

Author

Paul D. Hanna, Dec 27 2006

Keywords

• nonn

Crossrefs

Cf. A126465, A126466, A126468; A126469 (row sums).

Programs

PARI

{a(n)=local(M=matrix(n+2,n+2,r,c,if(r>=c,binomial((r-1)*r*(r+1)/3!-(c-1)*c*(c+1)/3!,r-c))), N=matrix(n+2,n+2,r,c,if(r>=c,binomial((r-1)*r*(r+1)/3!-(c-1)*c*(c+1)/3!+1,r-c)))); (N*M^-1)[n+2,2]}