A113992 - OEIS

A113992

Column 3 of triangle A113988, which is the matrix square of A113983: a(n) = [A113983^2](n+3,3).

%I #5 Jun 13 2017 23:38:10

%S 1,8,46,248,1366,7976,50186,342584,2541682,20478832,178809686,

%T 1687157648,17149281446,187185819536,2187084736978,27270946449584,

%U 361839376952194,5094730546999608,75927073509816766,1194793354659948104

%N Column 3 of triangle A113988, which is the matrix square of A113983: a(n) = [A113983^2](n+3,3).

%o (PARI) a(n)=local(A,B);A=Mat(1);for(m=2,n+4,B=matrix(m,m); for(i=1,m, for(j=1,i,if(i<3 || j==1 || j==i,B[i,j]=1, B[i,j]=A[i-1,j-1]+(A^2)[i-2,j-1] );));A=B);(A^2)[n+4,4]

%Y Cf. A113988, A113989 (column 0), A113990 (column 1), A113991 (column 2).

%K nonn

%O 0,2

%A _Paul D. Hanna_, Nov 12 2005