MathDB
Two weird numbers are coprime

Source: Kazakhstan National Olympiad (10-11).5

March 22, 2023
number theory

Problem Statement

Given are positive integers a,b,m,ka, b, m, k with k2k \geq 2. Prove that there exist infinitely many nn, such that gcd(φm(n),an+bk)=1\gcd (\varphi_m(n), \lfloor \sqrt[k] {an+b} \rfloor)=1, where φm(n)\varphi_m(n) is the mm-th iteration of φ(n)\varphi(n).