G.f. A(x) satisfies: 1 - x = Sum_{n>=0} x^n * (x^(2*n) + (-1)^n*A(x))^n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =8a(6) =15a(7) =27a(8) =54a(9) =107a(10) =211a(11) =429a(12) =870a(13) =1776a(14) =3669a(15) =7600a(16) =15832a(17) =33183a(18) =69766a(19) =147267a(20) =312000a(21) =662801a(22) =1412103a(23) =3016367a(24) =6457814a(25) =13856491a(26) =29792374a(27) =64174954a(28) =138483001a(29) =299324140