0,2

a(n) = A113346(n+1) - 1, where A113346 equals column 0 of triangle A113345 (=A113340^2).

(PARI) {a(n)=local(A, B); A=matrix(1, 1); A[1, 1]=1; for(m=2, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(i<3|j==i|j>m-1, B[i, j]=1, if(j==1, B[i, 1]=1, B[i, j]=(A^(2*j-1))[i-j+1, 1])); )); A=B); (matrix(#A, #A, r, c, if(r>=c, (A^(2*c))[r-c+1, 1]))^2)[n+1, 1]}

Cf. A113340, A113350, A113355, A113357 (column 1), A113358 (column 2), A113359 (column 3).

Sequence in context: A003708 A000986 A143920 this_sequence A062805 A053483 A052617

Adjacent sequences: A113353 A113354 A113355 this_sequence A113357 A113358 A113359

nonn

Paul D. Hanna (pauldhanna(AT)juno.com), Nov 08 2005