J(1)*theta3(z) where J(1) is the series given by A056948.

Terms

a(0) =1a(1) =2a(2) =0a(3) =-2a(4) =24a(5) =52a(6) =0a(7) =32556a(8) =195984a(9) =261626a(10) =0a(11) =3736682a(12) =16779168a(13) =18348900a(14) =0a(15) =103018596a(16) =397998672a(17) =376729140a(18) =0a(19) =1334328534a(20) =4629497040a(21) =3937811168a(22) =0a(23) =10792678852a(24) =34417510848a(25) =26962705262a(26) =0a(27) =62783490188a(28) =187489533504a(29) =138066125924