A121396 - OEIS

%I #3 Mar 30 2012 18:36:58

%S 1,1,2,5,16,75,594,8420,212790,9542280,763184598,109735708579,

%T 28582820337914,13580038203578493,11845224434439055236,

%U 19084161956327789507755,57113015617717986294647190

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

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

%o (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])}

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

%K nonn

%O 0,3

%A _Paul D. Hanna_, Jul 27 2006