What is woodall primes?

Woodall primes are a type of prime number that take the form of (2^n)-1, where n is also a prime number. They are named after mathematician John Woodall, who studied them in the 1960s. The first few Woodall primes are 3, 7, 23, 79, 383, 2,047, and 8,191. They are relatively rare and grow quickly in size as n increases. Like all prime numbers, Woodall primes are important in number theory and have applications in cryptography.