G.f.: A(x) = F(x*G(x)^2)^2 where F(x) = G(x/F(x)) = 1 + x*F(x)^2 is the g.f. of A000108 (Catalan) and G(x) = F(x*G(x)) = 1 + x*G(x)^3 is the g.f. of A001764.
A153297
G.f.: A(x) = F(x*G(x)^2)^2 where F(x) = G(x/F(x)) = 1 + x*F(x)^2 is the g.f. of A000108 (Catalan) and G(x) = F(x*G(x)) = 1 + x*G(x)^3 is the g.f. of A001764.
Terms
- a(0) =1a(1) =2a(2) =9a(3) =48a(4) =276a(5) =1656a(6) =10212a(7) =64190a(8) =409218a(9) =2637282a(10) =17143506a(11) =112224228a(12) =738926064a(13) =4889332266a(14) =32488240779a(15) =216664589058
External references
- oeis: A153297