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Message boards : Sierpinski/Riesel Base 5 Problem : Welcome to the Sierpinski / Riesel Base 5 Project

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Reggie
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Message 66386 - Posted: 5 Jun 2013 | 22:21:57 UTC

Welcome to the Sierpinski/Riesel Base 5 Project

This project is an extension of the original Sierpinski/Riesel problems (SoB/TRP). It is attempting to solve the Sierpinski/Riesel problems for base 5 by determining the smallest Sierpinski/Riesel numbers. Therefore, primes of the form k*5^n+/-1 are being sought for even k's.

A distributed effort is currently ongoing in support of the project. More information can be found in the mersenneforum.org Sierpinski/Riesel Base 5 thread.
Best of Luck!!!

Sierpinski Base 5 - The smallest even Sierpinski base 5 number is suggested to be k=159986. To prove this, it is sufficient to show that k*5^n+1 is prime for each even k < 159986. This has currently been achieved for all even k, with the exception of the following 30 values (as of 10 May 2020):
k = 6436, 7528, 10918, 26798, 29914, 31712, 36412, 41738, 44348, 44738, 45748, 51208, 58642, 60394, 62698, 64258, 67612, 67748, 71492, 74632, 76724, 83936, 84284, 90056, 92906, 93484, 105464, 126134, 139196, 152588

Riesel Base 5 - The smallest even Riesel base 5 number is suggested to be k=346802. To prove this, it is sufficient to show that k*5^n-1 is prime for each even k < 346802. This has currently been achieved for all even k, with the exception of the following 57 values (as of 19 June 2022):

k = 4906, 23906, 26222, 35248, 52922, 68132, 71146, 76354, 81134, 92936, 102952, 109238, 109862, 127174, 131848, 134266, 136804, 143632, 145462, 145484, 146756, 147844, 151042, 152428, 154844, 159388, 164852, 170386, 170908, 177742, 182398, 187916, 189766, 190334, 195872, 201778, 204394, 206894, 213988, 231674, 239062, 239342, 246238, 248546, 259072, 265702, 267298, 271162, 285598, 285728, 298442, 304004, 313126, 318278, 325922, 335414, 338866

History
Robert Smith originally presented the idea of a Sierpinski/Riesel base 5 search on 17 September 2004, in the primeform yahoo group. Using {3,7,13,31,601} as the covering set, he proposed that k=346802 is the smallest Riesel base 5 number. Shortly afterwards, Guido Smetrijns proposed that k=159986 is the smallest Sierpinski base 5 number.

After doing most of the initial work himself, Robert posted in the mersenneforum.org on 28 September 2004, and thus, the distributed effort began. Other principle players in the development, management, and growth of the project are Lars Dausch, Geoff Reynolds, Anand S Nair, and Thomas Masser.

Primes found by PrimeGrid

63838*5^3887851-1 found by Scott Lee on 19 June 2022 | Official Announcement
64598*5^3769854-1 found by Wes Hewitt on 14 June 2022
273662*5^3493296-1 found by Lukas Plätz on 7 December 2021 | Official Announcement
102818*5^3440382-1 found by Wes Hewitt on 8 October 2021 | Official Announcement
109838*5^3168862-1 found by Erik Veit on 13 August 2020 | Official Announcement
118568*5^3112069+1 found by Honza Cholt on 1 May 2020 | Official Announcement
207494*5^3017502-1 found by Todd Pickering on 16 March 2020 | Official Announcement
238694*5^2979422-1 found by Chris Howell on 12 March 2020 | Official Announcement
146264*5^2953282-1 found by Wolfgang Schwieger on 9 March 2020 | Official Announcement
35816*5^2945294-1 found by Pavel Atnashev on 5 March 2020 | Official Announcement
322498*5^2800819-1 found by Jordan Romaidis on 23 June 2019 | Official Announcement
88444*5^2799269-1 found by Scott Brown on 21 June 2019 | Official Announcement
138514*5^2771922+1 found by Ken Ito on 26 April 2019 | Official Announcement
194368*5^2638045-1 found by Honza Cholt on 15 August 2018 | Official Announcement
66916*5^2628609-1 found by Honza Cholt on 29 July 2018 | Official Announcement
81556*5^2539960+1 found by Jiří Bočan on 20 June 2018 | Official Announcement
327926*5^2542838-1 found by Seiya Tsuji on 19 June 2018 | Official Announcement
301562*5^2408646-1 found by Håkan Lind on 17 September 2017 | Official Announcement
171362*5^2400996-1 found by Frank Schwegler on 25 August 2017 | Official Announcement
180062*5^2249192-1 found by Stefan Larsson on 20 August 2016 | Official Announcement
53546*5^2216664-1 found by Tom Greer on 30 May 2016 | Official Announcement
296024*5^2185270-1 found by Steven Wong on 25 March 2016 | Official Announcement
92158*5^2145024+1 found by Karl Burridge on 15 March 2016 | Official Announcement
77072*5^2139921+1 found by Wolfgang Becker on 6 March 2016 | Official Announcement
306398*5^2112410-1 found by André Ahlfors Dahl on 11 January 2016 | Official Announcement
154222*5^2091432+1 found by Scott Brown on 10 November 2015 | Official Announcement
100186*5^2079747-1 found by Toshitaka Kumagai on 21 October 2015 | Official Announcement
144052*5^2018290+1 found by Wolfgang Schmidt on 23 May 2015 | Official Announcement
109208*5^1816285+1 found by Scott Brown on 18 October 2014 | Official Announcement
325918*5^1803339-1 found by Jörg Meili on 21 September 2014 | Official Announcement
133778*5^1785689+1 found by Guo Hua Miao on 17 August 2014 | Official Announcement
24032*5^1768249+1 found by Hiroyuki Okazaki on 23 July 2014 | Official Announcement
138172*5^1714207-1 found by Walter Darimont on 27 June 2014 | Official Announcement
22478*5^1675150-1 found by Guo Hua Miao on 19 June 2014 | Official Announcement
326834*5^1634978-1 found by Scott Brown on 25 April 2014 | Official Announcement
207394*5^1612573-1 found by Honza Cholt on 9 April 2014 | Official Announcement
104944*5^1610735-1 found by Brian Smith on 9 April 2014 | Official Announcement
330286*5^1584399-1 found by Scott Brown on 21 March 2014 | Official Announcement
22934*5^1536762-1 found by Keishi Toda on 6 February 2014 | Official Announcement
178658*5^1525224-1 found by Keishi Toda on 31 January 2014 | Official Announcement
59912*5^1500861+1 found by Raymond Ottusch on 17 January 2014 | Official Announcement
37292*5^1487989+1 found by Stephen R Cilliers on 29 December 2013 | Official Announcement
173198*5^1457792-1 found by Motohiro Ohno on 4 December 2013 | Official Announcement
245114*5^1424104-1 found by David Yost on 1 November 2013
175124*5^1422646-1 found by David Yost on 31 October 2013
256612*5^1335485-1 found by Wolfgang Schwieger on 4 August 2013
268514*5^1292240-1 found by Raymond Schouten on 16 July 2013
243944*5^1258576-1 found by Tod Slakans on 5 July 2013
97366*5^1259955-1 found by Jörg Meili on 4 July 2013
84466*5^1215373-1 found by Raymond Schouten on 29 June 2013
150344*5^1205508-1 found by Randy Ready on 28 June 2013
1396*5^1146713-1 found by Randy Ready on 23 June 2013
17152*5^1131205-1 found by Bob Benson on 22 June 2013
92182*5^1135262+1 found by Randy Ready on 21 June 2013
329584*5^1122935-1 found by Stephen R Cilliers on 21 June 2013
305716*5^1093095-1 found by Randy Ready on 18 June 2013
130484*5^1080012-1 found by Randy Ready on 17 June 2013
97768*5^987383-1 found by Ulrich Hartel on 17 June 2013
55154*5^1063213+1 found by Senji Yamashita on 16 June 2013
243686*5^1036954-1 found by Katsumi Hirai on 16 June 2013
70082*5^936972-1 found by Scott Brown on 30 May 2013
102976*5^929801-1 found by David Yost on 9 May 2013
110488*5^917100+1 found by Ronny Willig on 25 March 2013
162434*5^856004-1 found by Predrag Kurtovic on 10 January 2013
174344*5^855138-1 found by Ronny Willig on 9 January 2013
57406*5^844253-1 found by David Yost on 7 November 2012
48764*5^831946-1 found by David Yost on 12 October 2012
162668*5^785748-1 found by Lennart Vogel on 3 July 2012
289184*5^770116-1 found by David Yost on 7 June 2012
11812*5^769343-1 found by Göran Schmidt on 2 June 2012
316594*5^766005-1 found by Michael Becker on 30 May 2012
340168*5^753789-1 found by Kimmo Myllyvirta on 18 May 2012
338948*5^743996-1 found by Ricky L Hubbard on 7 May 2012
18656*5^735326-1 found by Lennart Vogel on 3 May 2012
5374*5^723697-1 found by Kelvin Lewis on 13 April 2012
72532*5^708453-1 found by Göran Schmidt on 7 February 2012
2488*5^679769-1 found by Sascha Beat Dinkel on 24 November 2011
331882*5^674961-1 found by Ronny Willig on 11 November 2011
27994*5^645221-1 found by Philipp Bliedung on 18 July 2011
262172*5^643342-1 found by Kimmo Myllyvirta on 13 July 2011
49568*5^640900-1 found by Sascha Beat Dinkel on 1 July 2011
270748*5^614625-1 found by Puzzle Peter on 14 February 2011
266206*5^608649-1 found by Puzzle Peter on 10 February 2011
210092*5^618136-1 found by Puzzle Peter on 31 January 2011
301016*5^586858-1 found by Puzzle Peter on 24 January 2011

Primes found by SR5 since collaboration

109988*5^544269+1 found by ltd on 23 April 2011
68492*5^542553+1 found by ltd on 24 April 2011

Primes found by others

3622 * 5^7558139-1 found by Ryan Propper on 18 February 2022
114986*5^1052966-1 found by Sergey Batalov on 3 June 2013
119878*5^1019645-1 found by Sergey Batalov on 3 June 2013

Michael Goetz
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Message 71263 - Posted: 6 Dec 2013 | 17:59:02 UTC

This thread has been updated with the most recent SR5 prime. This is the first SR5 megaprime!
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SteveRC

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Message 72473 - Posted: 20 Jan 2014 | 8:31:17 UTC - in response to Message 71263.

This thread has been updated with the most recent SR5 prime. This is the first SR5 megaprime!

Make that the second! - Congrats to Raymond!
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Message 72478 - Posted: 20 Jan 2014 | 9:24:53 UTC - in response to Message 72473.

This thread has been updated with the most recent SR5 prime. This is the first SR5 megaprime!

Make that the second! - Congrats to Raymond!

Raymond's was the third.
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Nick Embrey

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Message 78275 - Posted: 23 Jul 2014 | 16:24:37 UTC

Here's a (possibly dumb) question for you guys: Apparently there are some 25,000 SR5 tasks waiting to be turned into WUs. Plus the few thousand in progress. The "Waiting" number has been steadily falling. My question is, when this reaches zero, is that it? Is the SR5 project over? Or will new prime candidates be analyzed in the future beyond what's currently listed?

Sorry, I don't think I'm using the proper terminology but you guys know what I mean.
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Message 78276 - Posted: 23 Jul 2014 | 17:23:51 UTC - in response to Message 78275.

Here's a (possibly dumb) question for you guys: Apparently there are some 25,000 SR5 tasks waiting to be turned into WUs. Plus the few thousand in progress. The "Waiting" number has been steadily falling. My question is, when this reaches zero, is that it? Is the SR5 project over? Or will new prime candidates be analyzed in the future beyond what's currently listed?

Sorry, I don't think I'm using the proper terminology but you guys know what I mean.

More tasks will be loaded long before that number reaches zero. There's a lot more work available to be loaded -- several years worth, at least. We're currently around n=1.76M and we've sieved all the way to n=5M.

When we get close to n=5M, we'll do more sieving in order to create more ongoing tasks. This project, like all of the conjectures, will keep running until a prime is found for all k's (which will prove the conjecture is true.) If the conjecture is false, the project will never end.
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My lucky number is 75898524288+1

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Message 78277 - Posted: 23 Jul 2014 | 17:39:41 UTC - in response to Message 78276.

Thanks for that info.
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Michael Goetz
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Message 78278 - Posted: 23 Jul 2014 | 17:54:02 UTC - in response to Message 78277.

Thanks for that info.

You're welcome.

We don't expect to run out of work for any of the projects for several years, with two possible exceptions:

1) If there's a significant increase in the speed of testing for primes, either by some hardware innovation, an improvement to the LLR program, or a completely new algorithm, that would lower the "optimal sieve point" and further sieving on one of more projects might no longer be necessary. That could result in us shutting down a sieve project. (There's nothing like this on the horizon, so it's not likely.)

2) If we suddenly get very lucky and find a prime for all of the k's in one of the conjectures, that project will be complete and shut down. It could happen tomorrow, it could never happen, or anything inbetween. Chances are it won't be anytime soon.

Other than that, I expect all of our current BOINC projects to run for at least several years.
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My lucky number is 75898524288+1

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Message 99091 - Posted: 24 Sep 2016 | 8:02:57 UTC

Hello... I am oldjerryANO2011, Czech user - ID crossproject 12179, count 9 years, on account've almost 2 billion credits, of which 90% achieved on the 18 subprojects PrimeGrid. I try in vain to about the 19th sub - SRBase 5 - subprojects signed my account as non-existent. Nobody knows what needs to be done. Consult please...

William Lee

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Message 104448 - Posted: 1 Feb 2017 | 7:15:55 UTC - in response to Message 66386.

Can you tell me where does the URL exists?

Michael Goetz
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Message 104524 - Posted: 2 Feb 2017 | 16:34:29 UTC - in response to Message 104448.

Can you tell me where does the URL exists?

What URL? I'm afraid I don't understand your question.
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My lucky number is 75898524288+1

mackerel
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Message 104525 - Posted: 2 Feb 2017 | 16:41:25 UTC - in response to Message 104448.

If you want to participate in SR5 project, it is an option as part of PrimeGrid and doesn't have to be added as a separate project in BOINC. Go to "You account" then "Preference for this project" where you can choose which subprojects to take part in.

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Message 130698 - Posted: 26 Jun 2019 | 21:20:38 UTC

According to the 2019 Mega Primes forum thread, now (June 2019) we found the primes 88444 * 5^2799269 - 1 and 322498 * 5^2800819 - 1 (with almost 2 million digits each), so we got rid of k=88444 and k=322498 of the Riesel "part" of the SR5 conjecture, right ?
____________

"Accidit in puncto, quod non contingit in anno."
Something that does not occur in a year may, perchance, happen in a moment.

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Message 130699 - Posted: 26 Jun 2019 | 21:22:45 UTC - in response to Message 130698.

According to the 2019 Mega Primes forum thread, now (June 2019) we found the primes 88444 * 5^2799269 - 1 and 322498 * 5^2800819 - 1 (with almost 2 million digits each), so we got rid of k=88444 and k=322498 of the Riesel "part" of the SR5 conjecture, right ?

Correct. Various pages have yet to be updated.
____________
My lucky number is 75898524288+1

JimB
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Message 130718 - Posted: 27 Jun 2019 | 10:30:02 UTC - in response to Message 130698.

According to the 2019 Mega Primes forum thread, now (June 2019) we found the primes 88444 * 5^2799269 - 1 and 322498 * 5^2800819 - 1 (with almost 2 million digits each), so we got rid of k=88444 and k=322498 of the Riesel "part" of the SR5 conjecture, right ?

You can always see live data at http://www.primegrid.com/stats_sr5_llr.php, including all the primes found.

composite
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Message 130730 - Posted: 27 Jun 2019 | 19:13:45 UTC - in response to Message 130718.

According to the 2019 Mega Primes forum thread, now (June 2019) we found the primes 88444 * 5^2799269 - 1 and 322498 * 5^2800819 - 1 (with almost 2 million digits each), so we got rid of k=88444 and k=322498 of the Riesel "part" of the SR5 conjecture, right ?

You can always see live data at http://www.primegrid.com/stats_sr5_llr.php, including all the primes found.

In case anyone missed it, the live data page is one of the Range Statistics links on the Subproject status page in the PrimeGrid menu at the top/left sidebar of this page.

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Message 130804 - Posted: 30 Jun 2019 | 18:07:27 UTC - in response to Message 66386.

88444*5^2799269-1 found by Scott Brown on 21 April 2019 | Official Announcement

I think the date of discovery is wrong.

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Message 140073 - Posted: 3 May 2020 | 17:22:19 UTC

No discoveries for 9 months and then four in less than 2 weeks.
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Message 140074 - Posted: 3 May 2020 | 17:27:09 UTC - in response to Message 140073.

Five))
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Message 140086 - Posted: 4 May 2020 | 2:08:21 UTC - in response to Message 140073.

No discoveries for 9 months and then four in less than 2 weeks.

He's correct if he posted this a month ago.
Five))

Well, now it should be:
No discoveries for 9 months and then five in less than 2 months
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Message 151847 - Posted: 19 Oct 2021 | 14:04:45 UTC - in response to Message 140086.

It is interesting, will we have an official announcement for recently found prime 102818*5^3440382-1.

And also somehow there 340 waiting tasks for it:
https://www.primegrid.com/stats_sr5_llr.php

stream
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Message 151849 - Posted: 19 Oct 2021 | 14:33:58 UTC - in response to Message 151847.

It is interesting, will we have an official announcement for recently found prime 102818*5^3440382-1.

Yes, eventually.

And also somehow there 340 waiting tasks for it:
https://www.primegrid.com/stats_sr5_llr.php

These tasks were automatically blocked when prime was found, but must be manually deleted from database. I just did.

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Message 152485 - Posted: 4 Dec 2021 | 12:57:32 UTC

First post needs to be updated.

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Message 152560 - Posted: 8 Dec 2021 | 7:04:33 UTC - in response to Message 152485.

It sure does, second conjecture k gone in a very short while! (click)
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1281979 * 2^485014 + 1 is prime ... no further hits up to: n = 5,700,000

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Message 152783 - Posted: 24 Dec 2021 | 11:40:31 UTC - in response to Message 152560.

I noticed that there are 517 tasks waiting for 273662*5^n-1 but it is already eliminated:
https://www.primegrid.com/stats_sr5_llr.php

Thanks.

stream
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Message 152784 - Posted: 24 Dec 2021 | 13:38:56 UTC - in response to Message 152783.

I noticed that there are 517 tasks waiting for 273662*5^n-1 but it is already eliminated:

Thanks, removed. There are blocked candidates which should be removed from database manually.

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Message 152785 - Posted: 24 Dec 2021 | 13:39:53 UTC - in response to Message 152783.

I noticed that there are 517 tasks waiting for 273662*5^n-1 but it is already eliminated:
https://www.primegrid.com/stats_sr5_llr.php

Thanks.

Those can be ignored.

When a prime is found for a conjecture, such as SR5, we immediately suspend all the waiting candidates for that k without waiting for the prime to be verified. But we don't delete them immediately just in case the prime turns out to be an error, or, as is the case with some subprojects, the PRP isn't actually prime.

Once all the formalities are done, we circle back and remove the suspended candidates. Unless we forget, which I suspect is what happened here. Thanks for pointing it out!

Happy holidays!
____________
My lucky number is 75898524288+1

Message boards : Sierpinski/Riesel Base 5 Problem : Welcome to the Sierpinski / Riesel Base 5 Project