a(n) = Product_{i=1..n} 1 - i + n*(n - i + 1) - (n - 2*i + 1)*((n - i + 1) mod 2).
A382597
a(n) = Product_{i=1..n} 1 - i + n*(n - i + 1) - (n - 2*i + 1)*((n - i + 1) mod 2).
Terms
- a(0) =1a(1) =1a(2) =8a(3) =105a(4) =3840a(5) =181545a(6) =15814656a(7) =1635491025a(8) =261144576000
External references
- oeis: A382597