a(n) = Sum_{k=0..n} binomial(n, k)^3 * 3^(n-k) * k!.
A277386
a(n) = Sum_{k=0..n} binomial(n, k)^3 * 3^(n-k) * k!.
Terms
- a(0) =1a(1) =4a(2) =35a(3) =438a(4) =6873a(5) =127488a(6) =2703447a(7) =64121130a(8) =1674999009a(9) =47638235484
External references
- oeis: A277386