Expansion of Product_{k>=1} (1 + x^k)^(sigma_3(k)).

Terms

a(0) =1a(1) =1a(2) =9a(3) =37a(4) =137a(5) =487a(6) =1749a(7) =5901a(8) =19695a(9) =63832a(10) =202905a(11) =632689a(12) =1941394a(13) =5860868a(14) =17448558a(15) =51255292a(16) =148726841a(17) =426605755a(18) =1210569740a(19) =3400427281a(20) =9460683203a(21) =26083933370a(22) =71300381025a(23) =193313191005a(24) =520057831035