Expansion of Product_{k>=1} (1 + x^k)^(sigma_4(k)).

Terms

a(0) =1a(1) =1a(2) =17a(3) =99a(4) =491a(5) =2429a(6) =12056a(7) =56618a(8) =259074a(9) =1155193a(10) =5044288a(11) =21585280a(12) =90694483a(13) =374661505a(14) =1524090522a(15) =6111565745a(16) =24181962002a(17) =94491963120a(18) =364920615165