MathDB
f(m)+f(n)|m+n - Iran NMO 2004 (Second Round) - Problem4

Source:

September 24, 2010
functioninductionnumber theoryprime numbersnumber theory proposed

Problem Statement

N\mathbb{N} is the set of positive integers. Determine all functions f:NNf:\mathbb{N}\to\mathbb{N} such that for every pair (m,n)N2(m,n)\in\mathbb{N}^2 we have that: f(m)+f(n)  m+n.f(m)+f(n) \ | \ m+n .