Curious Squares

Abstract

A curious number is a palindromic number whose base ten representation has the form a . . . ab . . . ba . . . a. In this paper, we determine all curious numbers that are perfect squares. Our proof involves reducing the search for such numbers to several single variable families. From here, we complete the proof in two different ways. The first approach is elementary, though somewhat ad hoc. The second entails studying integral points on elliptic curves and is more systematic.