IMO 2013 Shortlist N1

Let Zą0 be the set of positive integers. Find all functions f : Zą0 Ñ Zą0 such that m2 fpnq | mfpmq n for all positive i...

IMO 2013 Shortlist N1

Category: Number Theory

Problem

Let Zą0 be the set of positive integers. Find all functions f : Zą0 Ñ Zą0 such that m2 fpnq | mfpmq n for all positive integers m and n. (Malaysia)