G.f. A(x) satisfies: A(x) = 1 / (1 + x) + x * A(x)^3.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =7a(5) =23a(6) =82a(7) =300a(8) =1129a(9) =4334a(10) =16914a(11) =66899a(12) =267586a(13) =1080516a(14) =4398850a(15) =18035084a(16) =74402361a(17) =308624282a(18) =1286428765a(19) =5385578256a(20) =22635057148a(21) =95471113565a(22) =403983783772