mersenneforum.org Some new Generalized Cullen and Woodall primes
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 2019-09-02, 17:43 #1 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 100100001010012 Posts Some new Generalized Cullen and Woodall primes (off-topic) It looks like PrimeGrid found either a Cullen or a Woodall. We will likely see it posted in a couple days. The n is apparently going to be even (in n*bn +/- 1, and n >> 17,000,000, so -- more than a 5 million digiter). Super! P.S. Well, this is a generalized Cullen ...slightly less exciting - but still very cool.
2019-09-02, 18:04   #2
paulunderwood

Sep 2002
Database er0rr

3,527 Posts

Quote:
 Originally Posted by Batalov (off-topic) It looks like PrimeGrid found either a Cullen or a Woodall. We will likely see it posted in a couple days. The n is apparently going to be even (in n*bn +/- 1, and n >> 17,000,000, so -- more than a 5 million digiter). Super!
I am looking forward to their publication of their new top 20 prime.

 2019-09-03, 06:49 #3 paulunderwood     Sep 2002 Database er0rr 3,527 Posts It is actually 3,921,539 digits (rank 21) and is being tested at UTM now. The newly discovered prime is 2805222*25^2805222+1 Serge played a part in this by noting that n*b^n+-1 can be tested quicker by testing n*(sqrt(b))^(2*n)+-1, by over 10% when using the LLR program.
2019-09-04, 00:40   #4
rudy235

Jun 2015
Vallejo, CA/.

2×5×97 Posts

Quote:
 Originally Posted by paulunderwood It is actually 3,921,539 digits (rank 21) and is being tested at UTM now. The newly discovered prime is 2805222*25^2805222+1 Serge played a part in this by noting that n*b^n+-1 can be tested quicker by testing n*(sqrt(b))^(2*n)+-1, by over 10% 0when using the LLR program.
Once verified (as far as UTM goes) it will be the largest prime discovered this year 2019.

It becomes the largest Generalized Cullen superseding the one discovered last year in March that had 2,913,785 digits.

Last fiddled with by rudy235 on 2019-09-04 at 00:51

 2019-09-04, 15:56 #5 LaurV Romulan Interpreter     Jun 2011 Thailand 3·17·179 Posts Yeaaa on the way to 100M digits! Any long way starts with a small step... Congrats!
 2019-09-05, 04:44 #6 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 100100001010012 Posts {blowhard mode on} My GW is still top 1! :-) {blowhard mode off /}
2019-09-11, 21:09   #7
rudy235

Jun 2015
Vallejo, CA/.

2·5·97 Posts

Quote:
 Originally Posted by rudy235 Once verified (as far as UTM goes) it will be the largest prime discovered this year 2019. It becomes the largest Generalized Cullen superseding the one discovered last year in March that had 2,913,785 digits. http://www.primegrid.com/download/gc41-1806676.pdf
Finally, we have the official announcement ready.

 2019-09-17, 12:33 #8 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 242916 Posts A generalized Woodall is on its way, too. (and it is a near-quasi-repdigit, too.) There could be a couple more in the bag - over a week or so.
2019-09-30, 21:26   #9
paulunderwood

Sep 2002
Database er0rr

3,527 Posts

Quote:
 Originally Posted by Batalov A generalized Woodall is on its way, too. (and it is a near-quasi-repdigit, too.) There could be a couple more in the bag - over a week or so.
Congrats to you and Ryan for the 3,028,951 digit prime 874208 *2916^874208 - 1

Last fiddled with by paulunderwood on 2019-09-30 at 21:33

 2019-10-26, 19:55 #10 paulunderwood     Sep 2002 Database er0rr 3,527 Posts Congrats ro Serge and Ryan for the 20th largest known prime: 2740879*32^2740879 - 1
2019-10-27, 05:04   #11
rudy235

Jun 2015
Vallejo, CA/.

3CA16 Posts

Quote:
 Originally Posted by paulunderwood Congrats ro Serge and Ryan for the 20th largest known prime: 2740879*32^2740879 - 1

It is the largest Generalized Woodall and with 4125441 digits it is the Third Prime with more than 4 million Digits (and < than 5M)
Congratulations to Ryan and Serge

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