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

Terms

a(0) =1a(1) =0a(2) =0a(3) =4a(4) =0a(5) =0a(6) =32a(7) =0a(8) =0a(9) =384a(10) =0a(11) =0a(12) =6912a(13) =0a(14) =0a(15) =202752a(16) =0a(17) =0a(18) =9060352a(19) =0a(20) =0a(21) =537133056a(22) =0a(23) =0a(24) =38729089024a(25) =0a(26) =0a(28) =0a(29) =0a(31) =0