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2015a^2+a = 2016b^2+b, \sqrt{a-b} is natural (HOMC 2016 J Q14)

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August 6, 2019
algebraradicalnatural

Problem Statement

Given natural numbers a,ba,b such that 2015a2+a=2016b2+b2015a^2+a = 2016b^2+b. Prove that ab\sqrt{a-b} is a natural number.