a(n) is the coefficient of x^(2*n-1) in the n-fold self-composition of G(x) = x + G(G(x))^3 = g.f. of A153851.

A153850

a(n) is the coefficient of x^(2*n-1) in the n-fold self-composition of G(x) = x + G(G(x))^3 = g.f. of A153851.

Terms

    a(0) =1a(1) =2a(2) =27a(3) =594a(4) =17180a(5) =603879a(6) =24795645a(7) =1160887350a(8) =60940292571

External references