{ "id": "2004.09155", "version": "v1", "published": "2020-04-20T09:32:04.000Z", "updated": "2020-04-20T09:32:04.000Z", "title": "A pair of congruences concerning sums of central binomial coefficients", "authors": [ "Guo-Shuai Mao", "Roberto Tauraso" ], "categories": [ "math.NT", "math.CO" ], "abstract": "In this paper, we prove the following congruences: for any prime $p\\equiv1\\pmod3$: $$\\sum_{k=1}^{\\lfloor\\frac{2p}3\\rfloor}\\binom{2k}{k}(-2)^k\\equiv0\\pmod{p^2}\\qquad \\text{ and }\\qquad \\sum_{k=0}^{\\lfloor\\frac{5p}6\\rfloor}\\frac{\\binom{2k}k}{(-32)^k}\\equiv\\left(\\frac2p\\right)\\pmod{p^2}$$ where $\\left(\\frac{\\cdot}{p}\\right)$ stands for the Legendre symbol.", "revisions": [ { "version": "v1", "updated": "2020-04-20T09:32:04.000Z" } ], "analyses": { "subjects": [ "11A07", "05A10", "11B65", "11G05", "33B15" ], "keywords": [ "central binomial coefficients", "congruences concerning sums", "legendre symbol" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }