Petkovšek, Marko, and Herbert S. Wilf. “When Can the Sum of $(1/P)$th of the Binomial Coefficients Have Closed Form?”. The Electronic Journal of Combinatorics 4, no. 2 (November 25, 1996): R21. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v4i2r21.