%I #2 Mar 30 2012 18:37:07

%S 1,2,7,40,326,3492,46558,744320,13889080,296459376,7125938790,

%T 190502850972,5607258255032,180198503713952,6278311585490032,

%U 235730921392184452,9489040823468191328,407662178549724426176

%N Column 1 of triangle A135080.

%C Triangle A135080 transforms diagonals in the table of coefficients of successive self-compositions of x+x^2 (cf. A122888).

%o (PARI) {a(n)=local(F=x,M,N,P); M=matrix(n+3,n+3,r,c,F=x;for(i=1,r+c-2,F=subst(F,x,x+x^2+x*O(x^(n+3))));polcoeff(F,c)); N=matrix(n+2,n+2,r,c,M[r,c]);P=matrix(n+2,n+2,r,c,M[r+1,c]);(P~*N~^-1)[n+2,2]}

%Y Cf. A135080 (triangle); other columns: A135081, A135083.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Nov 18 2007