Variations on a Hypergeometric Theme

Abstract

The question was asked: Is it possible to express the function \begin{equation} \tag{1.1} h(a)\equiv\,{_4F_3}(a,a,a,a;2a,a+1,a+1;1) \label{question} \end{equation} in closed form? After considerable analysis, the answer appears to be "no", but during the attempt to answer this question, a number of interesting (and unexpected) related results were obtained, either as specialized transformations, or as closed-form expressions for several related functions. The purpose of this paper is to record and review both the methods attempted and the related identities obtained (specifically new $_4F_3(1)$, $_5F_6(1)$ and (generalized Euler) sums containing digamma functions) - the former for their educational merit, since they appear to be not-very-well-known, the latter because they do not appear to exist in the literature.Comment: In this (second) revision, Appendix C is corrected. This paper has been accepted for publication in the (Open Access) Journal of Classical Analysi