Pythagoras number, also known as Pythagoras ternary number. Pythagoras number is a set of positive integers that can form three sides of a right triangle. Pythagorean number is based on Pythagorean theorem. Pythagorean theorem is one of the important mathematical theorems discovered and proved by human beings in the early days.

Pythagoras commonly used numbers are: 3, 4, 5; 5、 12、 13; 7、24、25; 8、 15、 17; 9,40,41and so on.