JBMO Shortlist 2020 N3
Source: JBMO Shortlist 2020
July 4, 2021
JuniorBalkanshortlist2020number theory
Problem Statement
Find the largest integer (), for which there exists an integer () such that from any collection of consecutive positive integers one can always choose numbers, which verify the following conditions:1. each chosen number is not divisible by , by , nor by ;
2. the positive difference of any two distinct chosen numbers is not divisible by at least one of the
numbers , , and .