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

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =5a(6) =8a(7) =11a(8) =15a(9) =24a(10) =34a(11) =43a(12) =63a(13) =87a(14) =115a(15) =159a(16) =217a(17) =279a(18) =380a(19) =505a(20) =657a(21) =868a(22) =1139a(23) =1458a(24) =1913a(25) =2482a(26) =3162a(27) =4069a(28) =5232a(29) =6628