Sum of two repdigits a square
Number Theory
2018-01-22 v1
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.
Keywords
Cite
@article{arxiv.1607.06681,
title = {Sum of two repdigits a square},
author = {Bart Goddard and Jeremy Rouse},
journal= {arXiv preprint arXiv:1607.06681},
year = {2018}
}
Comments
9 pages