Expansion of Product_{1 <= i < j} (1 + x^(i*j)).

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =1a(5) =2a(6) =3a(7) =3a(8) =5a(9) =6a(10) =8a(11) =10a(12) =14a(13) =16a(14) =22a(15) =28a(16) =33a(17) =43a(18) =55a(19) =64a(20) =84a(21) =102a(22) =123a(23) =153a(24) =188a(25) =224a(26) =277a(27) =335a(28) =401a(29) =486