a(n) = Sum_{k=0..floor(n/5)} (-1)^k * (n-5*k)!.
A358611
a(n) = Sum_{k=0..floor(n/5)} (-1)^k * (n-5*k)!.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =119a(6) =719a(7) =5038a(8) =40314a(9) =362856a(10) =3628681a(11) =39916081a(12) =478996562a(13) =6226980486a(14) =87177928344
External references
- oeis: A358611