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These primes are exceedingly rare and sporadic  said Chris Caldwell  a professor of mathematics and statistics at the University of Tennessee at Martin  who studies prime numbers and has written a history of the Mersenne primes.
"Finding a prime is not going to change any theorems in mathematics  but this is a type of prime that has been interesting to mathematicians since several centuries before Christ "  Caldwell  said. Even the ancient Greek mathematician Euclid talked about what would later become the Mersenne primes  he said.
 Caldwell  added that the discovery was akin to breaking a land speed record.
The last few Mersenne primes have been closer to each other than the researchers expected   he  said.
The numbers seem to occur sporadically because researchers don't fully understand the pattern they follow   he  said. "So you expect in any process that appears random to have some close groupings of numbers. But  we  didn't expect to find another one so soon after the last one."
"In the long run   we  hope to use these data to predict how often these occur "  he  added.
Output:
Largest known prime number discovered by FedEx employee