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

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =1a(5) =1a(6) =5a(7) =5a(8) =9a(9) =9a(10) =13a(11) =13a(12) =26a(13) =26a(14) =39a(15) =48a(16) =61a(17) =70a(18) =92a(19) =101a(20) =139a(21) =157a(22) =195a(23) =229a(24) =292a(25) =326a(26) =405a(27) =464a(28) =559a(29) =634