a(n) = Sum_{k=1..n} k*binomial(n, k)^3*(n^2 + n - k*n - k + k^2)/((n - k + 1)^2*n).
A201640
a(n) = Sum_{k=1..n} k*binomial(n, k)^3*(n^2 + n - k*n - k + k^2)/((n - k + 1)^2*n).
Terms
- a(0) =1a(1) =8a(2) =54a(3) =368a(4) =2550a(5) =17952a(6) =128086a(7) =924128a(8) =6729858a(9) =49395440a(10) =364979560a(11) =2712343680a(12) =20257516240a(13) =151957919232
External references
- oeis: A201640