mersenneforum.org Prime Gap News
 User Name Remember Me? Password
 Register FAQ Search Today's Posts Mark Forums Read

 2020-09-13, 22:18 #122 Bobby Jacobs     May 2018 3×5×13 Posts I hope you find the missing gaps.
 2020-09-18, 11:25 #123 mart_r     Dec 2008 you know...around... 19×31 Posts So now, as promised, some new large gaps, ready for a doublecheck: Code: 1363608 90547#/9699690-366998 900144 90583#/9699690-523646 971716 90647#/223092870-359938 1293962 90679#/223092870-873966 1029000 90697#/510510-336914 1442154 90703#/510510-582572 1898630 90709#/9699690-1271684 1028856 90749#/510510-694658 1018282 90749#/9699690-576318 1054830 90787#/510510-630698 948276 90803#/9699690-317680 I was placing a bet on finding a 2M+ gap, but no luck there. These "low grade" megagaps would have been easier to find with divisors 2310 or 30030. Something I've been wanting to ask years ago: there are still a couple of gaps from Patrick DeGeest's project (largest/smallest PRPs with d digits, also called "border PRPs") that are not included in the GitHub lists. I don't know whether someone is in contact with him to ask for inclusion of those gaps, or to include them anyway from the openly accessible data (I could make a list if need be), or to let it be anyone's concern...
2020-09-19, 10:26   #124
SethTro

"Seth"
Apr 2019

181 Posts

Quote:
 Originally Posted by mart_r So now, as promised, some new large gaps, ready for a doublecheck: Code: 1363608 90547#/9699690-366998 900144 90583#/9699690-523646 971716 90647#/223092870-359938 1293962 90679#/223092870-873966 1029000 90697#/510510-336914 1442154 90703#/510510-582572 1898630 90709#/9699690-1271684 1028856 90749#/510510-694658 1018282 90749#/9699690-576318 1054830 90787#/510510-630698 948276 90803#/9699690-317680 I was placing a bet on finding a 2M+ gap, but no luck there. These "low grade" megagaps would have been easier to find with divisors 2310 or 30030. Something I've been wanting to ask years ago: there are still a couple of gaps from Patrick DeGeest's project (largest/smallest PRPs with d digits, also called "border PRPs") that are not included in the GitHub lists. I don't know whether someone is in contact with him to ask for inclusion of those gaps, or to include them anyway from the openly accessible data (I could make a list if need be), or to let it be anyone's concern...
I lightly tested these (~1 in 2000 numbers + endpoints) and they are now merged in
https://github.com/primegap-list-pro...6e77e8f82a7715

 2020-09-19, 12:05 #125 mart_r     Dec 2008 you know...around... 58910 Posts Thanks! I'll be looking for smaller gaps for the rest of the year.
 2020-09-19, 19:07 #126 SethTro     "Seth" Apr 2019 181 Posts Megagaps proposal: I was rereading drtrnicely-format-legacy and I believe that Dr Nicely's solution was to label the gap 'C??' for conventional, unknown is first, "but the interior integers of the gap have not been verified all composite to the satisfaction of Thomas R. Nicely". I can easily change CloudyGo to verify the endpoints + some small percentage of the interior. Any objections to allowing these records with less verification and C?? status?
 2020-09-20, 14:34 #127 mart_r     Dec 2008 you know...around... 19×31 Posts Sounds okay to me. Is there an extra query available for all the yet not fully verified gaps?
 2020-09-20, 15:59 #128 ATH Einyen     Dec 2003 Denmark 296510 Posts When you find those megagaps do you sieve first before prp testing? If yes then please save those factors, so they can be verified easily afterwards. Last fiddled with by ATH on 2020-09-20 at 16:01
 2020-09-20, 20:13 #129 mart_r     Dec 2008 you know...around... 19·31 Posts It's only a crummy sieve via Pari, about 20 minutes to less than 1G, without keeping factors. But I definitely keep it in mind should I ever aim for a 10M gap.
2020-09-20, 23:11   #130
SethTro

"Seth"
Apr 2019

2658 Posts

Quote:
 Originally Posted by mart_r Sounds okay to me. Is there an extra query available for all the yet not fully verified gaps?
I'm not sure what you mean by extra query, I'm working to accept these records via the normal flow (with some UI warning they will be recorded C??)

Quote:
 Originally Posted by ATH When you find those megagaps do you sieve first before prp testing? If yes then please save those factors, so they can be verified easily afterwards.
It's easy for me to rerun the sieve on my side which is easier than accepting a giant list of offsets + small factor.

 2020-09-20, 23:19 #131 ATH Einyen     Dec 2003 Denmark 5·593 Posts Well it depends on how far they were sieved. Known factors can be checked very quickly. Sounds like the sieving is not really optimal, you should sieve until finding new factors takes longer than PRP testing the candidate.
2020-09-21, 15:06   #132
mart_r

Dec 2008
you know...around...

11158 Posts

Quote:
 Originally Posted by SethTro I'm not sure what you mean by extra query, I'm working to accept these records via the normal flow (with some UI warning they will be recorded C??)
I thought that one might want to have a quick check which gaps need verification.

Quote:
 Originally Posted by SethTro It's easy for me to rerun the sieve on my side which is easier than accepting a giant list of offsets + small factor.
I was also worried about the several megabytes those lists would take up.
Giving only the list of numbers with factors larger than 1G (say) would be a reasonable compromise, I guess. Depends on the depth of the sieve.

Quote:
 Originally Posted by ATH Sounds like the sieving is not really optimal, you should sieve until finding new factors takes longer than PRP testing the candidate.
Well, sieving takes about 20 minutes longer with a depth of 2G, I get 3.4% less candidates, and while every 8 hours a prime is found, that would save me 16 minutes there.
Sieving via Pari is not optimal, but since it's not really the bottleneck, I decided to leave it at that. Besides, it was not a big project like the gaps between prime twins and prime gaps in arithmetic progression...

Last fiddled with by mart_r on 2020-09-21 at 15:14

 Similar Threads Thread Thread Starter Forum Replies Last Post gd_barnes Conjectures 'R Us 293 2020-09-13 07:42 gd_barnes No Prime Left Behind 250 2020-06-29 13:23 willmore Computer Science & Computational Number Theory 48 2010-09-19 08:30 NBtarheel_33 Hardware 17 2009-05-04 15:52 MoZ Factoring 6 2006-02-28 12:02

All times are UTC. The time now is 15:34.

Tue Oct 20 15:34:44 UTC 2020 up 40 days, 12:45, 1 user, load averages: 3.37, 3.48, 3.47