A109156 - OEIS

%I #3 Mar 30 2012 18:36:49

%S 1,2,5,14,47,188,867,4460,25025,150890,967825,6554482,46600855,

%T 346228012,2677951311,21495038944,178565654041,1531692226714,

%U 13538763090277,123096619532030,1149440819867767,11007471611129700

%N Row sums of triangle A109152.

%C Triangular matrix T=A109152 satisfies: T(n,k) = [T^2](n-1,k) for n>k+1>=1, with T(n,n) = 1 and T(n+1,n) = n+1 for n>=0.

%o (PARI) {a(n)=local(M=matrix(n+1,n+1));M=M^0;for(i=1,n, M=matrix(n+1,n+1,r,c,if(r>=c,if(r==c,1,if(r==c+1,c,(M^2)[r-1,c]))))); return(sum(k=0,n,M[n+1,k+1]))}

%Y Cf. A109152 (triangle), A109153 (column 0), A109154 (column 1), A109155 (column 2).

%K nonn

%O 0,2

%A _Paul D. Hanna_, Jun 20 2005