a(n) = [x^n] (2*n)! * Sum_{k=0..2*n} binomial(x-2*n,k).

A347985

a(n) = [x^n] (2*n)! * Sum_{k=0..2*n} binomial(x-2*n,k).

Terms

    a(0) =1a(1) =-3a(2) =131a(3) =-8955a(4) =893249a(5) =-117408375a(6) =19180128407

External references