A121418 Column 0 of triangle A121416.

1, 2, 7, 43, 403, 5188, 85569, 1725291, 41145705, 1133047596, 35377360292, 1234796503280, 47636225803285, 2012509471127885, 92398547122062997, 4580472438441602301, 243822925502110419105, 13870297863425823346284

Offset: 0

Author

Paul D. Hanna, Aug 22 2006, Jan 19 2008

Keywords

• nonn

Comments

Also column 1 of square array A136733.

A121416 is the matrix square of triangle A121412; row n of triangle T=A121412 equals row (n-1) of T^(n+1) with an appended '1'.

Crossrefs

Cf. A121416 (triangle); other columns: A121418, A121419.

Cf. A136733; A101483, A121421; A121425.

Programs

PARI

{a(n)=local(A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i,j]=1, B[i, j]=(A^i)[i-1, j]); )); A=B); return((A^2)[n+1, 1])}

Extensions

Edited by N. J. A. Sloane, Oct 30 2008 at the suggestion of R. J. Mathar