MathDB
2017 Kosovo TST Problem 2

Source:

March 19, 2017
functionalgebra

Problem Statement

Prove that there doesn't exist any function f:NNf:\mathbb{N}\rightarrow \mathbb{N} such that : f(f(n1)=f(n+1)f(n)f(f(n-1)=f(n+1)-f(n), for every natural n2n\geq2