G.f. S(x) satisfies: C(C(x)) - S(S(x)) = x where C(x) = x + 2*x^2*S(x).

Terms

a(0) =0a(1) =2a(2) =0a(3) =0a(4) =16a(5) =0a(6) =0a(7) =192a(8) =0a(9) =0a(10) =3456a(11) =0a(12) =0a(13) =101376a(14) =0a(15) =0a(16) =4530176a(17) =0a(18) =0a(19) =268566528a(20) =0a(21) =0a(22) =19364544512a(23) =0a(24) =0a(26) =0a(27) =0a(29) =0a(30) =0a(32) =0