numbers 1 to 1000000 with color
Source:
March 28, 2009
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Problem Statement
Initially numbers from 1 to 1000000 are all colored black. A move consists of picking one number, then change the color (black to white or white to black) of itself and all other numbers NOT coprime with the chosen number. Can all numbers become white after finite numbers of moves?
Edited by pbornsztein