Series acceleration formulas for Dirichlet series with periodic coefficients

Abstract

Series acceleration formulas are obtained for Dirichlet series with periodic coefficients. Special cases include Ramanujan's formula for the values of the Riemann zeta function at the odd positive integers exceeding two, and related formulas for values of Dirichlet L-series and the Lerch zeta function. Such formulas have been made famous by Lerch, Ramanujan, Grosswald, Berndt, and others. The approach herein is based on the partial fraction expansion of the hyperbolic cotangent, and as such is somewhat more elementary than previous approaches, yet is quite general.