Expansion of f(f(x)), where f = x + x^2 + x^4 + x^8 + x^16 + ...

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =6a(5) =8a(6) =8a(7) =16a(8) =22a(9) =40a(10) =80a(11) =146a(12) =240a(13) =356a(14) =488a(15) =661a(16) =870a(17) =1184a(18) =1936a(19) =3750a(20) =7976a(21) =17628a(22) =37528a(23) =74828a(24) =140480a(25) =249444a(26) =420392a(27) =678432a(28) =1056600a(29) =1593512