MathDB
SMO Senior Round 2 Qn 5 2013

Source:

June 29, 2013

Problem Statement

Let x,yx,y be distinct real numbers such that xnynxy\frac{x^n-y^n}{x-y} is an integer for 44 consecutive positive integer nn. Prove that xnynxy\frac{x^n-y^n}{x-y} is an integer for all positive integers nn.