Expansion of 1 / (Sum_{n=-oo..oo} x^(n^2))^3.

Terms

a(0) =1a(1) =-6a(2) =24a(3) =-80a(4) =234a(5) =-624a(6) =1552a(7) =-3648a(8) =8184a(9) =-17654a(10) =36816a(11) =-74544a(12) =147056a(13) =-283440a(14) =535008a(15) =-990912a(16) =1803882a(17) =-3232224a(18) =5707624a(19) =-9943536a(20) =17106960a(21) =-29088352a(22) =48922320a(23) =-81438528a(24) =134261584a(25) =-219336630a(26) =355242288