G.f.: x * Sum_{k>=1} x^k / (1 - a(k)*x^k).

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =3a(7) =1a(8) =3a(9) =2a(10) =4a(11) =1a(12) =5a(13) =1a(14) =5a(15) =6a(16) =4a(17) =1a(18) =7a(19) =1a(20) =13a(21) =11a(22) =6a(23) =1a(24) =7a(25) =17a(26) =7a(27) =11a(28) =31a(29) =1