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

Terms

a(0) =1a(1) =2a(2) =8a(3) =22a(4) =62a(5) =154a(6) =392a(7) =914a(8) =2136a(9) =4776a(10) =10544a(11) =22626a(12) =47982a(13) =99538a(14) =204100a(15) =411714a(16) =821130a(17) =1616170a(18) =3148812a(19) =6066338a(20) =11579954a(21) =21893214a(22) =41045780a(23) =76306030a(24) =140783060a(25) =257789064a(26) =468783092a(27) =846697340a(28) =1519599658a(29) =2710476106