G.f. satisfies A(x) = 1 + x (1+Sum_{n=0..inf} [xA(x)]^(2^n)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =13a(7) =27a(8) =59a(9) =131a(10) =295a(11) =684a(12) =1609a(13) =3829a(14) =9203a(15) =22262a(16) =54179a(17) =132565a(18) =325823a(19) =804108a(20) =1991729a(21) =4949794a(22) =12339483a(23) =30851429a(24) =77347913a(25) =194422788a(26) =489892473a(27) =1237207811a(28) =3131186993a(29) =7940340037