Shur W. The Last Digit of ${2n \choose n}$ and $\sum {n \choose i}{2n-2i \choose n-i}$. Electron. J. Combin. [Internet]. 1996Nov.11 [cited 2026Mar.27];4(2):R16. Available from: https://www.combinatorics.org/ojs/index.php/eljc/article/view/v4i2r16