for each n, exactly 1 of n,2n,3n is element of A, 2 \in A, prove 13824 \notin A
Source: Dutch BxMO/EGMO TST 2012 p5
August 24, 2019
number theorycombinatoricsset
Problem Statement
Let be a set of positive integers having the following property:
for each positive integer exactly one of the three numbers and is an element of .
Furthermore, it is given that . Prove that .