IMO Shortlist 2010 problem A6
Dodao/la: arhiva23. lipnja 2013.
are two functions defined on the set of positive integers and taking positive integer values. Suppose also that the equations
hold for all positive integers. Prove that
for all positive integer
Proposed by Alex Schreiber, Germany
Izvor: Međunarodna matematička olimpijada, shortlist 2010