MathDB
IMO Shortlist 2013, Number Theory #4

Source: IMO Shortlist 2013, Number Theory #4

July 10, 2014
number theoryPerfect Squaredecimal representationIMO ShortlistHi

Problem Statement

Determine whether there exists an infinite sequence of nonzero digits a1,a2,a3,a_1 , a_2 , a_3 , \cdots and a positive integer NN such that for every integer k>Nk > N, the number akak1a1\overline{a_k a_{k-1}\cdots a_1 } is a perfect square.