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

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =9a(5) =14a(6) =21a(7) =31a(8) =45a(9) =65a(10) =92a(11) =127a(12) =175a(13) =239a(14) =322a(15) =430a(16) =572a(17) =753a(18) =985a(19) =1281a(20) =1657a(21) =2131a(22) =2727a(23) =3471a(24) =4401a(25) =5558a(26) =6988a(27) =8751a(28) =10924a(29) =13588