This works not only for n = 4 but also for any n.By using this formula, you can always get the nth prime number.. But so far I have suppressed one piece of information. We have assumed that a ...

The newly discovered number is what's known as a Mersenne prime, named for a French monk named Marin Mersenne who studied primes some 350 years ago. Mersenne primes have a simple formula: 2 n -1.