IMO 2010 Shortlist N5
Let N be the set of all positive integers. Find all functions f : N Ñ N such that the number fpmq n m fpnq is a squa...
Category: Number Theory
Problem
Let N be the set of all positive integers. Find all functions f : N Ñ N such that the number fpmq n m fpnq is a square for all m,n PN. (U.S.A.)