In the 1980s, the mathematician Ronald Graham asked if it’s possible to color each positive integer either red or blue, so that no triple of integers
obeying Pythagoras’ famous equation:
all have the same color. He offered a prize of $100.
Now it’s been solved! The answer is no. You can do it for numbers up to 7824, and a solution is shown in this picture. But you can’t do it for numbers up to 7825.
To prove this, you could try all the ways of coloring these numbers and show that noth...
Published on May 28, 2016 10:00