G.f. satisfies: A(x) = C(x)^2 * A(x^3*C(x)^4), where C(x) is the g.f. of the Catalan numbers (A000108).

A120899

G.f. satisfies: A(x) = C(x)^2 * A(x^3*C(x)^4), where C(x) is the g.f. of the Catalan numbers (A000108).

Terms

    a(0) =1a(1) =2a(2) =5a(3) =16a(4) =54a(5) =186a(6) =654a(7) =2338a(8) =8463a(9) =30938a(10) =114022a(11) =423096a(12) =1579049a(13) =5922512a(14) =22309350a(15) =84354388a(16) =320020227a(17) =1217689680a(18) =4645693038a(19) =17766596202a(20) =68092473570a(21) =261486788434

External references