bw painting integers, m white => m + 20 white, k black => k + 35 black
Source: Norwegian Mathematical Olympiad 2012 - Abel Competition p1b
September 4, 2019
number theorycombinatoricsColoring
Problem Statement
Every integer is painted white or black, so that if is white then is also white, and if is black then is also black. For which can exactly of the numbers be white?