a(n) = (-2)^n * Euler_polynomial(n,1) * binomial(2*n,n).

Terms

a(0) =1a(1) =-2a(2) =0a(3) =40a(4) =0a(5) =-4032a(6) =0a(7) =933504a(8) =0a(9) =-385848320a(10) =0a(11) =249576198144a(12) =0a(14) =0a(16) =0a(18) =0a(20) =0a(22) =0