Mersenne Primes

Mersenne Primes are prime number of the form (2^n) - 1. It is known that (2^n) - 1can only be prime if n itself is prime.
Currently (March 1999), 37 Mersenne Primes are known.

\(\(i = 1; s = SessionTime[]; 

    While[True, 

      If[PrimeQ[2^i - 1], 
        Print["Exponent: ", i, "
", "Mersenne Prime: ", 2^i - 1, 
          "
", SessionTime[] - s, " seconds (", 
          Floor[\((SessionTime[] - s)\)/60], " min.)"]; \(i++\), \(i++\)]
        
		]
\)\)

Helmut Knaust, 3-3-1999