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03-17-18, 11:49 AM
On 11 March 2018, 23:54:40 UTC, PrimeGrid’s Generalized Cullen/Woodall Prime Search found the largest known Generalized Cullen prime:1806676*41^1806676+1 (http://primes.utm.edu/primes/page.php?id=124515)Generalized Cullen numbers are of the form: n*b^n+1. Generalized Cullen numbers that are prime are called Generalized Cullen primes. For more information, please see “Cullen prime” in The Prime Glossary (http://primes.utm.edu/glossary/xpage/Cullens.html).The prime is 2,913,785 digits long and enters Chris Caldwell's The Largest Known Primes Database (http://primes.utm.edu/primes) ranked 1st for Generalized Cullen primes and 27th overall. Base 41 was one of 12 prime-less Generalized Cullen bases below b=121 that PrimeGrid is searching. The remaining bases are 13, 25, 29, 47, 49, 55, 69, 73, 101, 109 & 121. The discovery was made by Hiroyuki Okazaki (zunewantan (https://www.primegrid.com/show_user.php?userid=277353)) of Japan using an Intel(R) Xeon(R) E5-2670 CPU @ 2.60GHz with 4GB RAM, running Linux. This computer took about 7 hours and 13 minutes to complete the primality test using multithreaded LLR. Hiroyuki is a member of the Aggie The Pew (http://www.primegrid.com/team_display.php?teamid=2280) team.The prime was verified on 12 March 2018 09:07:23 UTC by Scott Brown (Scott Brown (https://www.primegrid.com/show_user.php?userid=1178)) of the United States using an Intel(R) CPU @ 2.30GHz with 16GB RAM, running Windows 10 Professional Edition. This computer took about 15 hours 22 minutes to complete the primality test using LLR. Scott is also a member of the Aggie The Pew (http://www.primegrid.com/team_display.php?teamid=2280) team. For more details, please see the official announcement (http://www.primegrid.com/download/gc41-1806676.pdf).
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