a(n) = n! * Sum_{k=0..floor(n/5)} (-n/5)^k / (k! * (n-5*k)!).

A362320

a(n) = n! * Sum_{k=0..floor(n/5)} (-n/5)^k / (k! * (n-5*k)!).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =-119a(6) =-863a(7) =-3527a(8) =-10751a(9) =-27215a(10) =7197121a(11) =96476689a(12) =689534209a(13) =3507486841a(14) =14238448225

External references