Expansion of Product_{n>=1} ((1 + 4*x^n)/(1 - 4*x^n))^(1/4).

Terms

a(0) =1a(1) =2a(2) =4a(3) =18a(4) =34a(5) =166a(6) =384a(7) =1902a(8) =4756a(9) =24022a(10) =64284a(11) =321542a(12) =899658a(13) =4455690a(14) =12888944a(15) =63185250a(16) =187513426a(17) =910880550a(18) =2759413788a(19) =13295839638a(20) =40967821494a(21) =195979968882a(22) =612569599440