A121429 Main diagonal of rectangular table A121428.

1, 2, 18, 250, 4520, 99351, 2556806, 75190410, 2483617140, 90955908010, 3655774038653, 159938142409890, 7564604603286913, 384576889110665055, 20912407157570989950, 1211142337261176799610, 74427504634177621877538

Offset: 0

Author

Paul D. Hanna, Aug 26 2006

Keywords

• nonn

Crossrefs

Cf. A121428, A121412.

Programs

PARI

{a(n)=local(H=Mat(1), B); for(m=1, n+3, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, B[i, j]=(H^i)[i-1, j]); )); H=B); return((H^(n+1))[n+3, 3])}

Formula

a(n) = [A121412^(n+1)](n+2,2) for n>=0; i.e., the (n+1)-th term of column 2 in matrix power A121412^(n+1).