G.f. satisfies A(x) = 1/(1 - 2*x) - x*A(x)^3.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =5a(6) =10a(7) =16a(8) =31a(9) =59a(10) =101a(11) =206a(12) =376a(13) =692a(14) =1408a(15) =2528a(16) =4943a(17) =9767a(18) =17755a(19) =35950a(20) =68659a(21) =129029a(22) =262758a(23) =490832a(24) =958948a(25) =1920580a(26) =3581020a(27) =7203080a(28) =14054600a(29) =26665160