Expansion of Sum_{k>=0} x^(k^2) * Product_{j=1..k} (1 + x^j)^j.

Terms

a(0) =1a(1) =1a(2) =1a(3) =0a(4) =1a(5) =1a(6) =2a(7) =2a(8) =1a(9) =2a(10) =1a(11) =2a(12) =5a(13) =4a(14) =7a(15) =9a(16) =7a(17) =10a(18) =9a(19) =9a(20) =13a(21) =13a(22) =18a(23) =27a(24) =31a(25) =42a(26) =53a(27) =61a(28) =71a(29) =83