English

On a $_2F_1\big(\frac{1}{4}\big)$-identity due to Gosper

Classical Analysis and ODEs 2026-04-07 v1

Abstract

It is only in exceptional cases that a 2F1(z)_2F_1(z)-series with rational parameters and a rational argument, apart from the cases for z{±1,12}z \in \{ \pm 1, \frac{1}{2} \} associated with classical hypergeometric identities, admits an evaluation given by a combination of Γ\Gamma-values with rational arguments. In this paper, we present a new and integration-based approach toward the construction of special values for 2F1_2F_1-series of the desired form. We apply this approach using a 2F1(14)_2F_1\big(\frac{1}{4}\big)-identity originally due to Gosper and later considered by Vidunas, Ebisu, and Zudilin, to evaluate a 2F1{}_{2}F_{1}-series of convergence rate (172872185039)2\big(\frac{172872}{185039}\big)^2. With regard to extant research on so-called ``strange'' 2F1{}_{2}F_{1}-evaluations, as in the work of Ebisu and Zeilberger, our new series seems to have the largest numerator/denominator in its argument.

Keywords

Cite

@article{arxiv.2604.04799,
  title  = {On a $_2F_1\big(\frac{1}{4}\big)$-identity due to Gosper},
  author = {Cetin Hakimoglu-Brown},
  journal= {arXiv preprint arXiv:2604.04799},
  year   = {2026}
}

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11 pages