a(n) = Sum_{k=0..n} binomial(n,k) * (2^k + 3)^k.

A251184

a(n) = Sum_{k=0..n} binomial(n,k) * (2^k + 3)^k.

Terms

    a(0) =1a(1) =6a(2) =60a(3) =1494a(4) =135960a(5) =53187306a(6) =90775495620

External references