A074728 a(n) = Sum_{k=1..n} k^(n-k)*binomial(n,k-1).

1, 3, 10, 39, 176, 903, 5174, 32623, 223792, 1655463, 13110758, 110510007, 986490272, 9287036671, 91872460702, 952034494431, 10305790066208, 116254839687543, 1363631057783942, 16599343732844455, 209328335818064176, 2730323984395924623, 36780442970179975646

Offset: 1

Author

Vladeta Jovovic, Sep 05 2002

Keywords

• nonn

Crossrefs

Cf. A000248.

Programs

Mathematica

Table[Sum[k^(n-k) Binomial[n,k-1],{k,n}],{n,30}] (* Harvey P. Dale, Mar 19 2013 *)

Formula

E.g.f.: (exp(x*exp(x))-exp(x))/x.