Expansion of Product_{k>=1} (1 + 2*x^k)/(1 - 2*x^k).

Terms

a(0) =1a(1) =4a(2) =12a(3) =36a(4) =92a(5) =228a(6) =540a(7) =1236a(8) =2748a(9) =6004a(10) =12876a(11) =27252a(12) =57036a(13) =118308a(14) =243564a(15) =498564a(16) =1015484a(17) =2060484a(18) =4167804a(19) =8409588a(20) =16934748a(21) =34049940a(22) =68378220a(23) =137185428a(24) =275026476a(25) =551052676a(26) =1103618508a(27) =2209525092a(28) =4422484764a(29) =8850120420