5

Boethius says in his De Arithmetica that the number 5 represents an infinite circle: “For 5 times 5, which makes 25, starts from 5 and ends in the same number, 5. And if you multiply that by 5 again, the end turns out to be 5 again. For 5 times 25 makes 125, and if you multiply by 5 again, the answer will end with the number 5. And this always happens up to infinity.”