A121396 Column 1 of triangle T=A121395, where column k of T equals column k of T^(2^k) shift down 1 row.

1, 1, 2, 5, 16, 75, 594, 8420, 212790, 9542280, 763184598, 109735708579, 28582820337914, 13580038203578493, 11845224434439055236, 19084161956327789507755, 57113015617717986294647190

Offset

0,3

Comments

Also equals column 1 of the matrix square of triangle A121395.

Links

Table of n, a(n) for n=0..16.

Prog

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

Crossrefs

Cf. A121395 (triangle), A121397 (column 2).

Sequence in context: A020127 A179500 A377569 * A371829 A263914 A218168

Adjacent sequences: A121393 A121394 A121395 * A121397 A121398 A121399

Keyword

nonn

Author

Paul D. Hanna, Jul 27 2006

Status

approved