Two closed-form evaluations for the generalized hypergeometric function ${}_4F_3(\frac1{16})$
Arjun K. Rathie, Mykola A. Shpot
TL;DR
This work derives two closed-form evaluations for ${}_4F_3(1/16)$ by exploiting an even/odd decomposition of ${}_3F_2$ and leveraging known ${}_3F_2(±1/4)$ results. The resulting formulas express ${}_4F_3(1/16)$ in terms of $\psi'(1/3)$ and $\pi^2$, and enable a faster-converging infinite-sum representation for $pi^2$ when combined. The approach reveals connections to Ramanujan-type sums and the Clausen function, enriching the interplay between hypergeometric sums, binomial/harmonic identities, and special functions. These findings extend explicit evaluation techniques for ${}_pF_q$ functions and may have applications in mathematical physics and analytic number theory.
Abstract
The objective of this short note is to provide two closed-form evaluations for the generalized hypergeometric function $_4F_3$ of the argument $\frac1{16}$. This is achieved by means of separating a generalized hypergeometric function $_3F_2$ into even and odd components, together with the use of two known results for $_3F_2(\pm\frac14)$ available in the literature. As an application, we obtain an interesting infinite-sum representation for the number $π^2$. Certain connections with the work of Ramanujan and other authors are discussed, involving other special functions and binomial sums of different kinds.
