A167018 Column 2 of triangle T=A167015: a(n) = T(n+2,2) = [T^(n+2)](n-1,0) for n>0 with a(0)=1.

1, 1, 4, 20, 149, 1491, 18612, 275856, 4699180, 89993827, 1907644760, 44253266889, 1113845999245, 30214252304871, 878483783958444, 27252652393849400, 898540310823301994, 31378570076570865074, 1157108876622296079054

Offset

0,3

Comments

In triangle T=A167015, row n of T equals the initial n terms in column 0 of matrix power T^n, reversed and with an appended '1'.

Links

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

Prog

(PARI) {A167015(n, k)=local(M, N); if(n==k||n==k+1, 1, if(n==k+2, k+2, N=matrix(n, n, r, c, if(r>=c, A167015(r-1, c-1))); M=matrix(n+1, n+1, r, c, if(r>=c, if(r<=n, N[r, c], (N^n)[n-k, 1]))); M[n+1, k+1]))}
{a(n)=A167015(n+2, 2)}

Crossrefs

Cf. A167015, A167016, A167017, A167019.

Sequence in context: A082988 A001171 A247331 * A094070 A335627 A119022

Adjacent sequences: A167015 A167016 A167017 * A167019 A167020 A167021

Keyword

nonn

Author

Paul D. Hanna, Oct 27 2009

Status

approved