G.f. A(x) satisfies A(x) = C(x) / (1 - x*A(x))^2, where C(x) is the g.f. of A000108.

A381875

G.f. A(x) satisfies A(x) = C(x) / (1 - x*A(x))^2, where C(x) is the g.f. of A000108.

Terms

    a(0) =1a(1) =3a(2) =13a(3) =66a(4) =368a(5) =2185a(6) =13570a(7) =87147a(8) =574241a(9) =3861286a(10) =26390591a(11) =182798850a(12) =1280387583a(13) =9053335674a(14) =64534088960a(15) =463249047099

External references