IMO 2011 Shortlist A5
Prove that for every positive integer n, the set {2,3,4,...,3n + 1} can be partitioned into n triples in such a way that...
Category: Algebra
Problem
Prove that for every positive integer n, the set {2,3,4,...,3n + 1} can be partitioned into n triples in such a way that the numbers from each triple are the lengths of the sides of some obtuse triangle.