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

Terms

a(0) =1a(1) =2a(2) =3a(3) =7a(4) =16a(5) =40a(6) =105a(7) =281a(8) =770a(9) =2147a(10) =6080a(11) =17431a(12) =50459a(13) =147265a(14) =432821a(15) =1279978a(16) =3806154a(17) =11373668a(18) =34136769a(19) =102863360a(20) =311065038a(21) =943740309a(22) =2871717550a(23) =8762164066a(24) =26801981013a(25) =82172139800a(26) =252470206882a(27) =777243596670