Expansion of e.g.f. theta_3^(5/2).

Terms

a(0) =1a(1) =5a(2) =15a(3) =15a(4) =105a(5) =1845a(6) =5175a(7) =-11025a(8) =363825a(9) =4011525a(10) =46734975a(11) =367203375a(12) =-909822375a(13) =105415435125