{ "id": "1607.06681", "version": "v1", "published": "2016-07-22T13:50:13.000Z", "updated": "2016-07-22T13:50:13.000Z", "title": "Sum of two repdigits a square", "authors": [ "Bart Goddard", "Jeremy Rouse" ], "comment": "9 pages", "categories": [ "math.NT" ], "abstract": "A \\emph{repdigit} is a natural number greater than 10 which has all of its base-10 digits the same. In this paper we find all examples of two repdigits adding to a square. The proofs lead to interesting questions about consecutive quadratic residues and non-residues, and provide an elementary application of elliptic curves.", "revisions": [ { "version": "v1", "updated": "2016-07-22T13:50:13.000Z" } ], "analyses": { "subjects": [ "11D61", "11G05", "11A63" ], "keywords": [ "natural number greater", "consecutive quadratic residues", "elementary application", "elliptic curves", "non-residues" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }