G.f. A(x) satisfies A(x) = (1 + 9*x*A(x)^2)^(1/3).

Terms

a(0) =1a(1) =3a(2) =9a(3) =18a(4) =0a(5) =-162a(6) =-567a(7) =0a(8) =8019a(9) =31590a(10) =0a(11) =-520506a(12) =-2160756a(13) =0a(14) =38480265a(15) =164549880a(16) =0a(17) =-3072083274a(18) =-13390246485a(19) =0a(20) =258054995016a(22) =0a(25) =0a(28) =0