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

Terms

a(0) =1a(1) =1a(2) =18a(3) =100a(4) =526a(5) =2546a(6) =12953a(7) =60929a(8) =282194a(9) =1265959a(10) =5580958a(11) =24057117a(12) =101922204a(13) =424244720a(14) =1739362261a(15) =7027590168a(16) =28017627428a(17) =110295521903a(18) =429110693519