Dr. Pepper
Member
In most cases you will not get a prime number when multiplying a few primes and adding 1. The exception is when one of the primes is 2, otherwise if you multiply a few primes and add 1 you will get an even number.
Am I to understand this as saying that 2 * any prime + 1 is a prime number?
Is 63 really a prime number? 63 = 1 + 2 * 31