{ "id": "1809.02430", "version": "v1", "published": "2018-09-07T12:14:17.000Z", "updated": "2018-09-07T12:14:17.000Z", "title": "Arithmetic Progressions with Restricted Digits", "authors": [ "Aled Walker", "Alexander Walker" ], "comment": "11 pages, submitted to American Mathematical Monthly", "categories": [ "math.NT", "math.CO" ], "abstract": "For an integer $b \\geqslant 2$ and a set $S\\subset \\{0,\\cdots,b-1\\}$, we define the Kempner set $\\mathcal{K}(S,b)$ to be the set of all non-negative integers whose base-$b$ digital expansions contain only digits from $S$. These well-studied sparse sets provide a rich setting for additive number theory, and in this paper we study various questions relating to the appearance of arithmetic progressions in these sets. In particular, for all $b$ we determine exactly the maximal length of an arithmetic progression that omits a base-$b$ digit.", "revisions": [ { "version": "v1", "updated": "2018-09-07T12:14:17.000Z" } ], "analyses": { "keywords": [ "arithmetic progression", "restricted digits", "digital expansions contain", "kempner set", "well-studied sparse sets" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }