MathDB
Function

Source: APMO 1995

March 11, 2006
functionmodular arithmeticalgebra unsolvedalgebra

Problem Statement

Find the minimum positive integer kk such that there exists a function ff from the set Z\Bbb{Z} of all integers to {1,2,k}\{1, 2, \ldots k\} with the property that f(x)f(y)f(x) \neq f(y) whenever xy{5,7,12}|x-y| \in \{5, 7, 12\}.