IMO Shortlist 2009 problem A3
Dodao/la: arhiva2. travnja 2012.
Determine all functions
from the set of positive integers to the set of positive integers such that, for all positive integers
, there exists a non-degenerate triangle with sides of lengths
(A triangle is non-degenerate if its vertices are not collinear.)
Proposed by Bruno Le Floch, France
Izvor: Međunarodna matematička olimpijada, shortlist 2009