MathDB
Floors are perfect squares

Source: ITAMO 2019 #4

May 3, 2019
algebraITAMO 2019

Problem Statement

Let x\lfloor x \rfloor denote the greatest integer less than or equal to x.x.
Let λ1\lambda \geq 1 be a real number and nn be a positive integer with the property that λn+1,λn+2,,λ4n\lfloor \lambda^{n+1}\rfloor, \lfloor \lambda^{n+2}\rfloor ,\cdots, \lfloor \lambda^{4n}\rfloor are all perfect squares.. Prove that λ\lfloor \lambda \rfloor is a perfect square..