E.g.f.: 2*cosh(1) - Sum_{n>=0} (1 + x^n)^n * exp(-x^n) / n!.

Terms

a(0) =1a(1) =0a(2) =0a(3) =-4a(4) =6a(5) =-8a(6) =0a(7) =-12a(8) =-8400a(9) =40304a(10) =0a(11) =-20a(12) =-12640320a(13) =-24a(14) =0a(15) =-50854003228a(16) =523588665600a(17) =-32a(18) =0a(19) =-36a(22) =0a(23) =-44a(26) =0a(29) =-56a(30) =0a(31) =-60a(34) =0