{ "id": "1609.06810", "version": "v1", "published": "2016-09-22T03:57:57.000Z", "updated": "2016-09-22T03:57:57.000Z", "title": "Hankel-type determinants for some combinatorial sequences", "authors": [ "Bao-Xuan Zhu", "Zhi-Wei Sun" ], "comment": "12 pages", "categories": [ "math.CO" ], "abstract": "In this paper we confirm several conjectures of Z.-W. Sun on Hankel-type determinants for some combinatorial sequences including Franel numbers, Domb numbers and Ap\\'ery numbers. For any nonnegative integer $n$, define \\begin{gather*}f_n:=\\sum_{k=0}^n\\binom nk^3,\\ D_n:=\\sum_{k=0}^n\\binom nk^2\\binom{2k}k\\binom{2(n-k)}{n-k}, \\\\b_n:=\\sum_{k=0}^n\\binom nk^2\\binom{n+k}k,\\ A_n:=\\sum_{k=0}^n\\binom nk^2\\binom{n+k}k^2. \\end{gather*} For $n=0,1,2,\\ldots$, we show that $6^{-n}|f_{i+j}|_{0\\leq i,j\\leq n}$ and $12^{-n}|D_{i+j}|_{0\\le i,j\\le n}$ are positive odd integers, and $10^{-n}|b_{i+j}|_{0\\leq i,j\\leq n}$ and $24^{-n}|A_{i+j}|_{0\\leq i,j\\leq n}$ are always integers.", "revisions": [ { "version": "v1", "updated": "2016-09-22T03:57:57.000Z" } ], "analyses": { "subjects": [ "05A10", "11A07", "11B65", "11C20", "15B99" ], "keywords": [ "combinatorial sequences", "hankel-type determinants", "apery numbers", "positive odd integers", "franel numbers" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }