Painting positive integers
Source: Mexican Mathematical Olympiad 2016-Problem 2
November 7, 2016
Problem Statement
A pair of positive integers is called guerrera, if there exists positive integers such that , and . For example the pair is guerrera cause , and . We paint the positive integers if the following order:We start painting the numbers and . If a positive integer is not painted and a positive is painted such that the pair is guerrera, we paint . Find all positive integers that can be painted.