a(n) = Sum_{k=0..n} binomial(n, k) * (2^k - 1)^k.

A251182

a(n) = Sum_{k=0..n} binomial(n, k) * (2^k - 1)^k.

Terms

    a(0) =1a(1) =2a(2) =12a(3) =374a(4) =52056a(5) =28885802a(6) =62696043492

External references