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Diagonal convergence of the remainder Padé approximants for the Hurwitz zeta function. (English) Zbl 07318741
Summary: The Hurwitz zeta function $$\zeta(s,a)$$ admits a well-known (divergent) asymptotic expansion in powers of $$1/a$$ involving the Bernoulli numbers. Using Wilson orthogonal polynomials, we determine an effective bound for the error made when this asymptotic series is replaced by nearly diagonal Padé approximants. By specialization, we obtain new fast converging sequences of rational approximations to the values of the Riemann zeta function at every integers $$\geq 2$$. The latter can be viewed, in a certain sense, as analogues of Apéry’s celebrated sequences of rational approximations to $$\zeta(2)$$ and $$\zeta(3)$$.
##### MSC:
 11Y60 Evaluation of number-theoretic constants 41A21 Padé approximation 11J72 Irrationality; linear independence over a field 41A60 Asymptotic approximations, asymptotic expansions (steepest descent, etc.)
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##### References:
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