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

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =13a(5) =27a(6) =54a(7) =98a(8) =174a(9) =335a(10) =572a(11) =1004a(12) =1733a(13) =2933a(14) =4916a(15) =8307a(16) =13470a(17) =22042a(18) =35851a(19) =57256a(20) =91462a(21) =145231a(22) =227667a(23) =355522a(24) =554058a(25) =853986a(26) =1313121a(27) =2010318a(28) =3057827a(29) =4627213