Expansion of Product_{i>=1, j>=1} (1 + x^(i*j)) * (1 + x^(2*i*j)).

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =10a(5) =16a(6) =31a(7) =47a(8) =81a(9) =126a(10) =204a(11) =308a(12) =487a(13) =720a(14) =1098a(15) =1613a(16) =2395a(17) =3461a(18) =5061a(19) =7213a(20) =10362a(21) =14633a(22) =20712a(23) =28926a(24) =40497a(25) =56000a(26) =77527a(27) =106349a(28) =145791a(29) =198339