In this paper we present a generalization of Faulhaber's formula to
sums of arbitrary complex powers

.
These summation
formulas for sums of the form

and

,
where

and

,
are based on a series acceleration involving Stirling numbers of the
first kind. While it is well-known that the corresponding expressions
obtained from the Euler-Maclaurin summation formula diverge, our summation
formulas are all very rapidly convergent.