On a result of Koecher concerning Markov-Ap\'ery type formulas for the Riemann zeta function

Abstract

Koecher in 1980 derived a method for obtaining identities for the Riemann zeta function at odd positive integers, including a classical result for $\zeta(3)$ due to Markov and rediscovered by Ap\'ery. In this paper we extend Koecher's method to a very general setting and prove two more specific but still rather general results. As applications we obtain infinite classes of identities for alternating Euler sums, further Markov-Ap\'ery type identities, and identities for even powers of $\pi$