Find some numbers whose product is a perfect square
Source: IMO LongList 1988, Vietnam 6, Problem 94 of ILL
November 9, 2005
number theoryprime numbersPerfect SquareIMO Longlist
Problem Statement
Let positive integers be formed by taking the product of given prime numbers (a prime number can appear several times or also not appear at all in a product formed in this way.) Prove that among these one can find some numbers whose product is a perfect square.