Integers in Infinite Chessboard
Source: All-Russian MO 2003 Grade 11 #6
January 2, 2012
geometryrectangleanalytic geometrycombinatorics unsolvedcombinatorics
Problem Statement
Is it possible to write a positive integer in every cell of an infinite chessboard, in such a manner that, for all positive integers , the sum of numbers in every rectangle is divisible by ?