2025/05/20 by John M. Campbell, Campbell, John M. · 1 citation
Engineering · Mathematics · #Advanced Numerical Analysis Techniques #FOS: Mathematics #Iterative Methods for Nonlinear Equations #Number Theory (math.NT) #Numerical methods for differential equations
paper · pdf · doi:10.48550/arxiv.2505.14392
openalex publication_date 2025/05/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Each of Ramanujan's series for \frac1π is of the form ∑n=0∞ zn \frac (a1)n (a2)n (a3)n (b1)n (b2)n (b3)n (c1 n + c2) for rational parameters such that the difference between the arguments of any lower and upper Pochhammer symbols is not an integer. In accordance with the work of Chu, if an infinite sum of this form admits a closed form, then this provides a formula of Ramanujan type. Chu has introduced remarkable results on formulas of Ramanujan type, through the use of accelerations based on Ω-sums related to classical hypergeometric identities. Building on our past work on an acceleration method due to Wilf relying on inhomogeneous difference equations derived from Zeilberger's algorithm, we extend this method through what we refer to as an iterative approach that is inspired by Chu's accelerations derived using iteration patterns for well-poised Ω-sums and that we apply to introduce and prove many accelerated formulas of Ramanujan type for universal constants, along with many further accelerations related to the discoveries of Ramanujan, Guillera, and Chu.