MathDB
2018 PAMO Shortlist: Sequence eventually contains a square

Source: 2018 Pan-African Shortlsit - A7

May 6, 2019
algebranumber theoryIterationInteger sequence

Problem Statement

Let f(n)=n+nf(n) = n + \lfloor \sqrt{n} \rfloor. Prove that for every positive integer mm, the integer sequence m,f(m),f(f(m)),m, f(m), f(f(m)), \dots contains at least one square of an integer.