Expansion of Product_{k>=1} ((1 + 4*x^k) / (1 - 4*x^k))^(1/2).

Terms

a(0) =1a(1) =4a(2) =12a(3) =52a(4) =156a(5) =612a(6) =2028a(7) =7892a(8) =27324a(9) =107396a(10) =384844a(11) =1520436a(12) =5566876a(13) =22069796a(14) =81990252a(15) =325707348a(16) =1222582268a(17) =4862950020a(18) =18395472460a(19) =73233825524a(20) =278700724764