Expansion of 1 / (Sum_{n=-oo..oo} x^(n^2))^4.

Terms

a(0) =1a(1) =-8a(2) =40a(3) =-160a(4) =552a(5) =-1712a(6) =4896a(7) =-13120a(8) =33320a(9) =-80872a(10) =188784a(11) =-425952a(12) =932640a(13) =-1988080a(14) =4137024a(15) =-8422848a(16) =16810536a(17) =-32943760a(18) =63482760a(19) =-120440608a(20) =225217904a(21) =-415498496a(22) =756920160a(23) =-1362645440a(24) =2425895712