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

Terms

a(0) =1a(1) =-2a(2) =0a(3) =-10a(4) =22a(5) =-102a(6) =84a(7) =-950a(8) =3360a(9) =-18006a(10) =21968a(11) =-162126a(12) =613830a(13) =-2772010a(14) =3847740a(15) =-38669210a(16) =145735622a(17) =-567469350a(18) =901506480a(19) =-6688787966a(20) =27166965906a(21) =-137118406226a(22) =234942672620