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arXiv · 1607.06681

Sum of two repdigits a square

Bart Goddard·Jeremy Rouse
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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.

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Bart Goddard, Jeremy Rouse. 2016-07-22. Sum of two repdigits a square. https://arxiv.org/abs/1607.06681

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