G.f. A(x) satisfies: A(x)^3 = x * A( A(x)^2 + A(x)^3 ).

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =20a(5) =72a(6) =274a(7) =1084a(8) =4413a(9) =18365a(10) =77773a(11) =334065a(12) =1451929a(13) =6373379a(14) =28214851a(15) =125826137a(16) =564736106a(17) =2549004457a(18) =11563003842a(19) =52688331678a(20) =241049183598