The Secret of the Prime Pyramid
An ancient pyramid has a numerical puzzle engraved on its entrance. The puzzle states that there are three prime numbers, each less than 20, that form a unique set. The sum of these three prime numbers is equal to the square of the smallest prime number in the set. What are these three prime numbers? Remember, a prime number is a number greater than 1 that has no positive divisors other than 1 and itself.