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

Terms

a(0) =0a(1) =0a(2) =1a(3) =6a(4) =21a(5) =60a(6) =148a(7) =334a(8) =702a(9) =1396a(10) =2660a(11) =4880a(12) =8687a(13) =15044a(14) =25470a(15) =42212a(16) =68724a(17) =110000a(18) =173522a(19) =269930a(20) =414812a(21) =630032a(22) =947007a(23) =1409266a(24) =2078335a(25) =3038540a(26) =4407334a(27) =6344176a(28) =9068278a(29) =12874676