jmc

Question

A Mersenne prime is defined to be a prime number of the form 2^n - 1, where n must itself be a prime. For example, since 2^3 - 1 = 7, and 3 is a prime number, 7 is a Mersenne prime. What is the largest Mersenne prime less than 200?

Accepted Answer

The largest Mersenne Prime less than 200 is 2^7 - 1 = 128 - 1 = 127. The next possible Mersenne Prime, 2^11 - 1 = 2047, is much too large (and is not prime).