a(n) = 1 + Sum_{k=1..n} binomial(n,k) * 3^k * k^k.
A277456
a(n) = 1 + Sum_{k=1..n} binomial(n,k) * 3^k * k^k.
Terms
- a(0) =1a(1) =4a(2) =43a(3) =847a(4) =23881a(5) =870721a(6) =38894653a(7) =2055873037a(8) =125480383153
External references
- oeis: A277456