5

Part of 2018 Polish Junior MO First Round

Problems(1)

Coloring integers by three colors

Source: XIII Polish Junior MO 2018 First Round - Problem 5

Each integer should be colored by one of three colors, including red. Each number which can be represent as a sum of two numbers of different colors should be red. Each color should be used. Is this coloring possible?

combinatoricsColoringPoland