A121429 - OEIS

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

%S 1,2,18,250,4520,99351,2556806,75190410,2483617140,90955908010,

%T 3655774038653,159938142409890,7564604603286913,384576889110665055,

%U 20912407157570989950,1211142337261176799610,74427504634177621877538

%N Main diagonal of rectangular table A121428.

%F 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).

%o (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])}

%Y Cf. A121428, A121412.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Aug 26 2006