G.f.: A(x) = F(x*G(x)) where F(x) = G(x*F(x)) = 1 + x*F(x)^3 is the g.f. of A001764 and G(x) = F(x/G(x)) = 1 + x*G(x)^2 is the g.f. of A000108 (Catalan).

A153299

G.f.: A(x) = F(x*G(x)) where F(x) = G(x*F(x)) = 1 + x*F(x)^3 is the g.f. of A001764 and G(x) = F(x/G(x)) = 1 + x*G(x)^2 is the g.f. of A000108 (Catalan).

Terms

    a(0) =1a(1) =1a(2) =4a(3) =20a(4) =111a(5) =657a(6) =4067a(7) =26028a(8) =170913a(9) =1145446a(10) =7804797a(11) =53911104a(12) =376669462a(13) =2657391772a(14) =18904566514a(15) =135460704648a(16) =976795422828

External references