G.f. C(C(x)) where C(x) is the g.f. of A191417.

Terms

a(0) =1a(1) =0a(2) =0a(3) =8a(4) =0a(5) =0a(6) =128a(7) =0a(8) =0a(9) =2560a(10) =0a(11) =0a(12) =60416a(13) =0a(14) =0a(15) =1728512a(16) =0a(17) =0a(18) =63438848a(19) =0a(20) =0a(21) =3096477696a(22) =0a(23) =0a(24) =196811685888a(25) =0a(26) =0a(28) =0a(29) =0a(31) =0