Expansion of (Sum_{n=-inf..inf} x^(n^2))^(-13).

Terms

a(0) =1a(1) =-26a(2) =364a(3) =-3640a(4) =29094a(5) =-197288a(6) =1177176a(7) =-6333184a(8) =31258604a(9) =-143374530a(10) =617193304a(11) =-2513060264a(12) =9739727816a(13) =-36115518376a(14) =128680223152a(15) =-442158402816