G.f.: Sum_{k>=0} x^(2^k) / Product_{j=1..2^k} (1 - x^j).

Terms

a(0) =0a(1) =1a(2) =2a(3) =2a(4) =4a(5) =4a(6) =6a(7) =7a(8) =11a(9) =12a(10) =17a(11) =20a(12) =27a(13) =32a(14) =42a(15) =50a(16) =66a(17) =78a(18) =99a(19) =119a(20) =150a(21) =179a(22) =223a(23) =267a(24) =329a(25) =393a(26) =480a(27) =572a(28) =695a(29) =826