Incorrect answer - Mersenne primes

[MightyBalian]

@Sabrina

Sorry we never replied to the previous thread, the answer posted in that thread was the correct answer.

@Mattio

In the table, p is the exponent and M p is the actual prime number, the 15th number( M p = 21279 - 1) would be the first Mersenne prime exponent over 1000, not the actual prime number which is 386 digits long.

That post you just linked proves you wrong, though. 1279 is the first Mersenne exponent over 1000, not the first Mersenne prime. The first Mersenne prime over 1000 is 8191.