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

Terms

a(0) =1a(1) =-1a(2) =0a(3) =-1a(4) =2a(5) =-2a(6) =1a(7) =-2a(8) =4a(9) =-4a(10) =3a(11) =-4a(12) =8a(13) =-8a(14) =6a(15) =-9a(16) =14a(17) =-14a(18) =12a(19) =-16a(20) =24a(21) =-25a(22) =22a(23) =-28a(24) =40a(25) =-42a(26) =38a(27) =-48a(28) =65a(29) =-68