G.f.: 1/Product_{k>=1} (1 - x^(3*k^2)) * (1 - x^k).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =6a(5) =9a(6) =15a(7) =21a(8) =31a(9) =45a(10) =63a(11) =87a(12) =123a(13) =165a(14) =224a(15) =302a(16) =401a(17) =528a(18) =698a(19) =906a(20) =1177a(21) =1520a(22) =1950a(23) =2488a(24) =3173a(25) =4010a(26) =5061a(27) =6363a(28) =7965a(29) =9932