G.f.: exp( Sum_{n>=1} x^n/n * Product_{k>=1} (1 + x^(n*k)*(1 + x^k)^n) ).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =14a(6) =25a(7) =44a(8) =79a(9) =137a(10) =237a(11) =408a(12) =689a(13) =1162a(14) =1946a(15) =3231a(16) =5342a(17) =8776a(18) =14340a(19) =23326a(20) =37758a(21) =60847a(22) =97670a(23) =156145a(24) =248697a(25) =394719a(26) =624343a(27) =984360a(28) =1547187a(29) =2424581