{ "id": "1701.07016", "version": "v1", "published": "2017-01-24T03:36:08.000Z", "updated": "2017-01-24T03:36:08.000Z", "title": "Factors of sums involving $q$-binomial coefficients and powers of $q$-integers", "authors": [ "Victor J. W. Guo", "Su-Dan Wang" ], "comment": "10 pages", "categories": [ "math.CO", "math.NT" ], "abstract": "We show that, for all positive integers $n_1, \\ldots, n_m$, $n_{m+1}=n_1$, and any non-negative integers $j$ and $r$ with $j\\leqslant m$, the expression $$ \\frac{1}{[n_1]}{n_1+n_{m}\\brack n_1}^{-1} \\sum_{k=1}^{n_1}[2k][k]^{2r}q^{jk^2-(r+1)k}\\prod_{i=1}^{m} {n_i+n_{i+1}\\brack n_i+k} $$ is a Laurent polynomial in $q$ with integer cofficients, where $[n]=1+q+\\cdots+q^{n-1}$ and ${n\\brack k}=\\prod_{i=1}^k(1-q^{n-i+1})/(1-q^i)$. This gives a $q$-analogue of a divisibility result on the Catalan triangle obtained by the first author and Zeng, and also confirms a conjecture of the first author and Zeng. We further propose several related conjectures.", "revisions": [ { "version": "v1", "updated": "2017-01-24T03:36:08.000Z" } ], "analyses": { "subjects": [ "05A30", "05A10", "11B65" ], "keywords": [ "binomial coefficients", "first author", "integer cofficients", "divisibility result", "catalan triangle" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }