{ "id": "1611.01358", "version": "v1", "published": "2016-11-04T12:58:21.000Z", "updated": "2016-11-04T12:58:21.000Z", "title": "On some divisibility properties of binomial sums", "authors": [ "Brian Y. Sun" ], "comment": "12 pages; to appear in IJNT; comments are welcome from everyone", "categories": [ "math.CO", "math.NT" ], "abstract": "In this paper, we consider two particular binomial sums \\begin{align*} \\sum_{k=0}^{n-1}(20k^2+8k+1){\\binom{2k}{k}}^5 (-4096)^{n-k-1} \\end{align*} and \\begin{align*} \\sum_{k=0}^{n-1}(120k^2+34k+3){\\binom{2k}{k}}^4\\binom{4k}{2k} 65536^{n-k-1}, \\end{align*} which are inspired by two series for $\\frac{1}{\\pi^2}$ obtained by Guillera. We consider their divisibility properties and prove that they are divisible by $2n^2 \\binom{2n}{n}^2$ for all integer $n\\geq 2$. These divisibility properties are stronger than those divisibility results found by He, who proved the above two sums are divisible by $2n \\binom{2n}{n}$ with the WZ-method.", "revisions": [ { "version": "v1", "updated": "2016-11-04T12:58:21.000Z" } ], "analyses": { "subjects": [ "11A05", "11A07", "05A10", "11B65" ], "keywords": [ "divisibility properties", "binomial sums", "divisibility results" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }