a(n) = [x^n] ( c(x)/c(-x) )^n, where c(x) = (1 - sqrt( 1 - 4*x))/(2*x) is the o.g.f. of the Catalan numbers A000108.

A333564

a(n) = [x^n] ( c(x)/c(-x) )^n, where c(x) = (1 - sqrt( 1 - 4*x))/(2*x) is the o.g.f. of the Catalan numbers A000108.

Terms

    a(0) =2a(1) =8a(2) =56a(3) =384a(4) =2752a(5) =20096a(6) =148864a(7) =1114112a(8) =8403968a(9) =63787008a(10) =486584320a(11) =3727196160a(12) =28649455616a(13) =220869853184

External references