G.f.: A(x) = Sum_{n>=0} x^n / Product_{d|n} (1 - x^d)^(n/d).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =18a(6) =39a(7) =81a(8) =170a(9) =355a(10) =748a(11) =1576a(12) =3334a(13) =7054a(14) =14935a(15) =31591a(16) =66732a(17) =140708a(18) =296379a(19) =624389a(20) =1317807a(21) =2790095a(22) =5930254a(23) =12652077a(24) =27071714a(25) =58019282a(26) =124377335a(27) =266404590a(28) =569755992a(29) =1216513200