OFFSET
0,2
FORMULA
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.
PROG
(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]}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 03 2006
STATUS
approved