A124462 - OEIS

%I #3 Mar 30 2012 18:37:01

%S 1,3,8,23,73,251,919,3549,14371,60720,266481,1209807,5662008,27238884,

%T 134391046,678739990,3503708942,18462855900,99211177417,543161148837,

%U 3027439667989,17167987227428,98995692542858,580166879766649

%N Row 2 of rectangular table A124460.

%F G.f.: A(x) = Sum_{n>=0} x^n*R_n(x)^2, where R_n(x) is the g.f. of row n in table A124460 and satisfies: R_n(x) = Sum_{k>=0} x^k * R_k(x)^n for n>=0.

%o (PARI) {a(n)=local(m=max(n,2),R=vector(m+1,r,vector(m+1,c,binomial(r+c-2,c-1)))); for(i=0,m,for(r=0,m,R[r+1]=Vec(sum(c=0,m,x^c*Ser(R[c+1])^r+O(x^(m+1))))));R[3][n+1]}

%Y Cf. A124460 (table); other rows: A124461, A124463, A124464, A124465, A124466.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Nov 03 2006