{ "id": "1011.3487", "version": "v8", "published": "2010-11-15T19:59:35.000Z", "updated": "2015-02-26T15:49:34.000Z", "title": "Supercongruences motivated by e", "authors": [ "Zhi-Wei Sun" ], "comment": "16 pages", "journal": "J. Number Theory 147(2015), 326-341", "categories": [ "math.NT", "math.CO" ], "abstract": "In this paper we establish some new supercongruences motivated by the well-known fact $\\lim_{n\\to\\infty}(1+1/n)^n=e$. Let $p>3$ be a prime. We prove that $$\\sum_{k=0}^{p-1}\\binom{-1/(p+1)}k^{p+1}\\equiv 0\\ \\pmod{p^5}\\ \\ \\ \\mbox{and}\\ \\ \\ \\sum_{k=0}^{p-1}\\binom{1/(p-1)}k^{p-1}\\equiv \\frac{2}{3}p^4B_{p-3}\\ \\pmod{p^5},$$ where $B_0,B_1,B_2,\\ldots$ are Bernoulli numbers. We also show that for any $a\\in\\mathbb Z$ with $p\\nmid a$ we have $$\\sum_{k=1}^{p-1}\\frac1k\\left(1+\\frac ak\\right)^k\\equiv -1\\pmod{p}\\ \\ \\ \\mbox{and}\\ \\ \\ \\sum_{k=1}^{p-1}\\frac1{k^2}\\left(1+\\frac ak\\right)^k\\equiv 1+\\frac 1{2a}\\pmod{p}.$$", "revisions": [ { "version": "v7", "updated": "2014-07-21T14:19:56.000Z", "abstract": "In this paper we establish some new supercongruences motivated by the well-known fact $\\lim_{n\\to\\infty}(1+1/n)^n=e$. Let $p>3$ be a prime. We show that $$\\sum_{k=0}^{p-1}\\binom{-1/(p+1)}k^{p+1}\\equiv 0\\ \\pmod{p^5}\\ \\ \\ \\mbox{and}\\ \\ \\ \\sum_{k=0}^{p-1}\\binom{1/(p-1)}k^{p-1}\\equiv \\frac{2}{3}p^4B_{p-3}\\ \\pmod{p^5},$$ where $B_0,B_1,B_2,\\ldots$ are Bernoulli numbers. For any integer $m\\not\\equiv0\\pmod{p}$, we prove that $$\\sum_{k=0}^{p-1}(-1)^{km}\\binom{p/m-1}k^m\\equiv\\frac{(m-1)(7m-5)}{36m^2}p^4B_{p-3}\\pmod{p^5},$$ and $$\\sum_{k=1}^{p-1}\\frac{(-1)^{km}}{k^2}\\binom{p/m-1}k^m\\equiv\\frac 1p\\sum_{k=1}^{p-1}\\frac 1k\\ \\pmod{p^3}\\ \\ \\ \\ \\mbox{if}\\ p>5.$$ We also show that for any $a\\in\\mathbb Z$ with $p\\nmid a$ we have $$\\sum_{k=1}^{p-1}\\frac1k\\left(1+\\frac ak\\right)^k\\equiv -1\\pmod{p}\\ \\ \\ \\mbox{and}\\ \\ \\ \\sum_{k=1}^{p-1}\\frac1{k^2}\\left(1+\\frac ak\\right)^k\\equiv 1+\\frac 1{2a}\\pmod{p}.$$", "comment": "16 pages, revised version for publication. See Theorems 1.1-1.2 for new additions", "journal": null, "doi": null }, { "version": "v8", "updated": "2015-02-26T15:49:34.000Z" } ], "analyses": { "subjects": [ "11B65", "11A07", "05A10", "11B68" ], "keywords": [ "supercongruences", "well-known fact", "bernoulli numbers" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1011.3487S" } } }