MathDB
TOT 038 1983 Spring J-A5 4 in 5, are divisible by others or not, of 17

Source:

August 18, 2019
number theorydivisibleDividecombinatorics

Problem Statement

Prove that in any set of 1717 distinct natural numbers one can either find five numbers so that four of them are divisible into the other or five numbers none of which is divisible into any other.
(An established theorem)