Einmal ohne Übersetzung (evtl. kommt diese noch, aber definitiv nicht heute):

Welcome to PrimeGrid's 16th Birthday Challenge

The fourth challenge of the 2021 Series will be a5-daychallenge celebrating the 16th anniversary of the launch of PrimeGrid on BOINC. The challenge will be offered on theESP-LLRapplication, beginning12 June 13:00 UTCand ending17 June 13:00 UTC.

On 12 June 2005, at approximately 14:00 UTC, Message@Home (now PrimeGrid) opened account creation to 50 users. It was being run on Rytis’ home laptop. Message@Home was developed as a test project for PerlBOINC, an attempt to implement the BOINC server system in the Perl programming language. As such, a project was needed that provided a short WU with a standard consistent result. The first was Message7, and it attempted by “brute-force” to recover a message encoded with the md5 algorithm.

On September 1st, 2005, after a short contest to select a new project name, the PrimeGrid name was chosen from a variation of PrimeGrid@Home submitted by Heffed. He was awarded 999 cobblestones for his submission.

One year later, in June 2006, dialog started with Riesel Sieve to bring their project to the BOINC community. Rytis provided PerlBOINC support and RS was successful in implementing their sieve as well as a prime finding (LLR) application. With collaboration from RS, PrimeGrid was able to implement the LLR application in partnership with another prime finding project, Twin Prime Search. In November 2006, the TPS LLR application was officially released at PrimeGrid, and the rest is history! (no really, there's so much more than I could fit here and it's fascinating! check out the link for more.)

To participate in the Challenge, please select only theExtended Sierpinski Problem LLR (ESP)project in yourPrimeGrid preferencessection.

Note on LLR2 tasks:LLR2 has eliminated the need for a full doublecheck task on each workunit, but has replaced it with a short verification task. Expect to receive a few tasks about 1% of normal length.

Application buildsare available forLinux32 and 64 bit,Windows32 and 64 bit andMacIntel. Intel and recent AMD CPUs with FMA3 capabilities (Haswell or better for Intel, Zen-2 or better for AMD) will have a very large advantage, and Intel CPUs with dual AVX-512 (certain recent Intel Skylake-X and Xeon CPUs) will be the fastest.

Note that LLR is running the latest AVX-512 version of LLR which takes full advantage of the features of these newer CPUs. It's faster than the previous LLR app and draws more power and produces more heat, especially if they're highly overclocked.If you have certain recent Intel Skylake-X and Xeon CPUs, especially if it's overclocked or has overclocked memory, and haven't run the new AVX-512 LLR before, we strongly suggest running it before the challenge while you are monitoring the temperatures.

Multi-threading is supported and IS recommended.(ESP tasks on one CPU core will take 2-3 days on fast/newer computers and 1 week+ on slower/older computers.)

Those looking to maximize their computer's performance during this challenge, or when running LLR in general, may find this information useful.

- * Your mileage may vary.
Beforethe challenge starts, take some time and experiment and see what works best onyourcomputer.

* If you have a CPU with hyperthreading or SMT, either turn off this feature in the BIOS, or set BOINC to use 50% of the processors.*

- *If you're using a GPU for other tasks, it may be beneficial to leave hyperthreading on in the BIOS and instead tell BOINC to use 50% of the CPU's. This will allow one of the hyperthreads to service the GPU.
The new multi-threading system is now live. Click here to set the maximum number of threads.This will allow you to select multi-threading from the project preferences web page. No more app_config.xml. It works like this:* If you want to continue to use app_config.xml for LLR tasks, you need to change it if you want it to work. Please see this message for more information.

- * In the preferences selection, there are selections for "max jobs" and "max cpus", similar to the settings in app_config.

* Unlike app_config, these two settings apply to ALL apps. You can't chose 1 thread for SGS and 4 for SoB. When you change apps, you need to change your multithreading settings if you want to run a different number of threads.

* There will be individual settings for each venue (location).

* This will eliminate the problem of BOINC downloading 1 task for every core.

* The hyperthreading control isn't possible at this time.

* The "max cpus" control will only apply to LLR apps. The "max jobs" control applies to all apps.

* Some people have observed that when using multithreaded LLR, hyperthreading is actually beneficial. We encourage you to experiment and see what works best for you.Time zone converter:

The World Clock - Time Zone Converter

NOTE: The countdown clock on the front page uses the host computer time. Therefore, if your computer time is off, so will the countdown clock. For precise timing, use the UTC Time in the data section at the very top, above the countdown clock.

Scoring Information

Scores will be kept for individuals and teams. Only tasks issued AFTER 12th June 2021 13:00 UTC and received BEFORE 17th June 2021 13:00 UTC will be considered for credit. We will be using the same scoring method as we currently use for BOINC credits. A quorum of 2 isNOTneeded to award Challenge score - i.e. no double checker. Therefore, each returned result will earn a Challenge score. Please note that if the result is eventually declared invalid, the score will be removed.

At the Conclusion of the Challenge

- We kindly ask users "moving on" to ABORT their tasks instead of DETACHING, RESETTING, or PAUSING.

ABORTING tasks allows them to be recycled immediately; thus a much faster "clean up" to the end of an LLR Challenge. DETACHING, RESETTING, and PAUSING tasks causes them to remain in limbo until they EXPIRE. Therefore, we must wait until tasks expire to send them out to be completed.

Please consider eithercompleting what's in the queueor ABORTING them. Thank you.About the Extended Sierpinski Project

Wacław Franciszek Sierpiński (14 March 1882 - 21 October 1969), a Polish mathematician, was known for outstanding contributions to set theory, number theory, theory of functions and topology. It is in number theory where we find the Sierpinski problem.

Basically, the Sierpinski problem is "What is the smallest Sierpinski number" and the prime Sierpinski problem is "What is the smallest'prime'Sierpinski number?"

First we look at Proth numbers (named after the French mathematician François Proth). A Proth number is a number of the form k*2^n+1 where k is odd, n is a positive integer, and 2^n>k.

A Sierpinski number is an odd k such that the Proth number k*2^n+1 is not prime for all n. For example, 3 is not a Sierpinski number because n=2 produces a prime number (3*2^2+1=13). In 1962, John Selfridge proved that 78,557 is a Sierpinski number...meaning he showed that for all n, 78557*2^n+1 was not prime.

Most number theorists believe that 78,557 is the smallest Sierpinski number, but it hasn't yet been proven. In order to prove it, it has to be shown that every single k less than 78,557 is not a Sierpinski number, and to do that, some n must be found that makes k*2^n+1 prime.

The smallest proven'prime'Sierpinski number is 271,129. In order to prove it, it has to be shown that every single'prime'k less than 271,129 is not a Sierpinski number, and to do that, some n must be found that makes k*2^n+1 prime.

Should both of these problems be solved, k = 78557 will be established as the smallest Sierpinski number, and k = 271129 will be established as the smallest prime Sierpinski number. However, this would not prove that k = 271129 is the second provable Sierpinski number. Since the prime Sierpinski problem is testing all prime k's for 78557 < k < 271129, all that's needed is to test the composite k's for 78557 < k < 271129. Thus, theExtended Sierpinski Problemis established.

The following k's remain for each project:

[pre]Sierpinski problem (SoB) Prime Sierpinski problem (PSP) Extended Sierpinski Problem (ESP)

21181 22699* 91549

22699 67607* 131179

24737 79309 163187

55459 79817 200749

67607 152267 202705

156511 209611

222113 227723

225931 229673

237019 238411

*being tested by Seventeen or Bust[/pre]

Additional Information

For more information about Sierpinski, Sierpinski number, and the Sierpinsk problem, please see these resources:

- *
Waclaw Franciszek Sierpinski(WIKI)

*Sierpinski number / The Sierpinski problem(WIKI)

*The Sierpinski problem(Prothsearch)What is LLR?

The Lucas-Lehmer-Riesel (LLR) test is a primality test for numbers of the form N = k*2^n − 1, with 2^n > k. Also, LLR is a program developed by Jean Penne that can run the LLR-tests. It includes the Proth test to perform +1 tests and PRP to test non base 2 numbers. See also:

- *
Lucas-Lehmer-Riesel test(WIKI)

*Download LLRby Jean PennéWhat is LLR2?

LLR2 is an improvement to the LLR application developed by our very own Pavel Atnashev and stream. It utilizes Gerbicz checks to enable the Fast DoubleCheck feature, which will nearly double the speed of PrimeGrid's progress on the projects it's applied to. For more information, see this forum post.