On 29 Jan 2012, 08:10:03 UTC, PrimeGrid?s PRPNet found the largest known generalized Cullen prime: <b><a href="http://primes.utm.edu/primes/page.php?id=104121" rel="nofollow">427194*113^427194+1</a></b>

The prime is 877,069 digits long and enters Chris Caldwell's <b><a href="http://primes.utm.edu/primes" rel="nofollow">The Largest Known Primes Database</a></b> ranked 1st for generalized Cullen primes and 57th overall.

The discovery was made by <b>Ricky L. Hubbard</b> of the United States using an AMD Phenom II X6 1090t @ 3.2GHz with 8GB RAM, running Windows 7. This computer took 7 hours and 15 minutes to complete the probable prime test using pfgw64 and 7 hours 20 minutes to complete the primality test again using pfgw64. Ricky is a member of the <b><a href="http://www.primegrid.com/team_display.php?teamid=14" rel="nofollow">AMD Users</a></b> Team.

For more details, please see the <b><a href="http://www.primegrid.com/download/gc113-427194.pdf" rel="nofollow">official announcement</a></b>.