Welcome to Euler's Number Challenge

The eighth challenge of the 2021 Series will be a 3-day challenge in Thanksgiving™ of the anniversary of the introduction of e, or Euler's Number! The challenge will be offered on the AP27 Search subproject, beginning 23 November 05:00 UTC and ending 26 November 05:00 UTC.

2.71828182845904523536028747135266249775724709369995...
Euler's Number (not to be confused with Euler's Constant) is ubiquitous throughout seemingly unrelated fields of mathematics (not the least of which is prime numbers!) In reality, though, we've only been using this number since about 1690, and it only received its characteristic abbreviation e in Leonard Euler's letter to Christian Goldbach on November 25th, 1731.

Arithmetic progressions
In mathematics, an arithmetic progression (AP) or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant. For instance, the sequence 5, 7, 9, 11, 13, 15 … is an arithmetic progression with common difference of 2.

An arithmetic progression of primes is a sequence of primes with a common difference between any two successive numbers in the sequence. For example 3, 7, 11 is an arithmetic progression of 3 primes with a common difference of 4.

For an arithmetic progression (AP) of primes, AP-k is k primes of the form p + d*n for some d (the common difference between the primes) and k consecutive values of n. The above AP-3 is 3 + 4*n for n=0,1,2.

How to Participate?
To participate in the Challenge, please select only the AP 27 (AP27) project in your PrimeGrid preferences section. Application builds are available for Linux , Windows and MacIntel CPUs and GPUs. CPU apps are only available for 64 bit CPUs. High end Nvidia GPUs will have a very large advantage.

Tasks will take ~26 hours on average for CPUs and ~4 hours on average for GPUs. If your computer is highly overclocked, please consider "stress testing" it. If you haven't run the AP app before, we strongly suggest running it before the challenge while you are monitoring the temperatures. You don't want to turn your machine into a meteor!

Please, please, please make sure your machines are up to the task.

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 23 November 05:00 UTC and received BEFORE 26 November 05:00 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 is NOT needed 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 a 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 either completing what's in the queue or ABORTING them. Thank you. :)

For more information about the AP27 search, please visit these links:
- AP 27 Search
- AP 26 Search
- http://en.wikipedia.org/wiki/Arithmetic_progression
- Jens Kruse Andersen's Primes in Arithmetic Progression Records
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Time flies like an arrow. Fruit flies like a banana.

1 day down, 2 days to go, and we're churning out tasks!

Challenge: Euler's Number
App: 11 (AP27)
(As of 2021-11-24 07:17:19 UTC)

139015 tasks have been sent out. [CPU/GPU/anonymous_platform: 24811 (18%) / 114204 (82%) / 0 (0%)]

Of those tasks that have been sent out:

2699 (2%) were aborted. [2424 (2%) / 275 (0%) / 0 (0%)]
1867 (1%) came back with some kind of an error. [95 (0%) / 1772 (1%) / 0 (0%)]
107398 (77%) have returned a successful result. [6652 (5%) / 100746 (72%) / 0 (0%)]
27054 (19%) are still in progress. [15640 (11%) / 11414 (8%) / 0 (0%)]

Of the tasks that have been returned successfully:

19749 (18%) are pending validation. [1408 (1%) / 18341 (17%) / 0 (0%)]
87587 (82%) have been successfully validated. [5241 (5%) / 82346 (77%) / 0 (0%)]
44 (0%) were invalid. [2 (0%) / 42 (0%) / 0 (0%)]
18 (0%) are inconclusive. [1 (0%) / 17 (0%) / 0 (0%)]
____________

Time flies like an arrow. Fruit flies like a banana.

Entering day 3/3:

Challenge: Euler's Number
App: 11 (AP27)
(As of 2021-11-25 05:47:18 UTC)

246720 tasks have been sent out. [CPU/GPU/anonymous_platform: 37652 (15%) / 209068 (85%) / 0 (0%)]

Of those tasks that have been sent out:

3710 (2%) were aborted. [2950 (1%) / 760 (0%) / 0 (0%)]
4129 (2%) came back with some kind of an error. [108 (0%) / 4021 (2%) / 0 (0%)]
205897 (83%) have returned a successful result. [14241 (6%) / 191656 (78%) / 0 (0%)]
32987 (13%) are still in progress. [20353 (8%) / 12634 (5%) / 0 (0%)]

Of the tasks that have been returned successfully:

26896 (13%) are pending validation. [2033 (1%) / 24863 (12%) / 0 (0%)]
178885 (87%) have been successfully validated. [12205 (6%) / 166680 (81%) / 0 (0%)]
113 (0%) were invalid. [3 (0%) / 110 (0%) / 0 (0%)]
8 (0%) are inconclusive. [0 (0%) / 8 (0%) / 0 (0%)]
____________

Time flies like an arrow. Fruit flies like a banana.

A few hours left in the challenge! Some friendly reminders... :)

At the Conclusion of the Challenge

When the challenge completes, we would prefer users "moving on" to finish those tasks they have downloaded, if not then please ABORT the WU's (and then UPDATE the PrimeGrid project) instead of DETACHING, RESETTING, or PAUSING.

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

Likewise, if you're shutting down the computer for an extended period of time, or deleting the VM (Virtual Machine), please ABORT all remaining tasks first. Also, be aware that merely shutting off a cloud server doesn't stop the billing. You have to destroy/delete the server if you don't want to continue to be charged for it.

Thank you!
____________

Time flies like an arrow. Fruit flies like a banana.

And we're done! Final stats below, cleanup starting now!

Challenge: Euler's Number
App: 11 (AP27)
(As of 2021-11-26 04:50:15 UTC)

338642 tasks have been sent out. [CPU/GPU/anonymous_platform: 45903 (14%) / 292739 (86%) / 0 (0%)]

Of those tasks that have been sent out:

8924 (3%) were aborted. [7318 (2%) / 1606 (0%) / 0 (0%)]
5072 (1%) came back with some kind of an error. [112 (0%) / 4960 (1%) / 0 (0%)]
296923 (88%) have returned a successful result. [22079 (7%) / 274844 (81%) / 0 (0%)]
27725 (8%) are still in progress. [16394 (5%) / 11331 (3%) / 0 (0%)]

Of the tasks that have been returned successfully:

27692 (9%) are pending validation. [2195 (1%) / 25497 (9%) / 0 (0%)]
269042 (91%) have been successfully validated. [19881 (7%) / 249161 (84%) / 0 (0%)]
181 (0%) were invalid. [3 (0%) / 178 (0%) / 0 (0%)]
14 (0%) are inconclusive. [0 (0%) / 14 (0%) / 0 (0%)]
____________

Time flies like an arrow. Fruit flies like a banana.

What if two teams are tied at the end of the year?
At the current numbers, if AC finishes 80 points behind TAAT in the last challenge (P3 and P1) they will be level on points. Will the number of challenge wins be the determinant?
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My lucky number is 6219*2^3374198+1

What if two teams are tied at the end of the year?
At the current numbers, if AC finishes 80 points behind TAAT in the last challenge (P3 and P1) they will be level on points. Will the number of challenge wins be the determinant?

In case of ties, be it for teams or individuals, the tied entities end up sharing the same rank.
AFAIK, that's the way it was being done since 2008, when I took over generating these overall stats about 3 years ago.
I don't know in which order they'll appear in the table (need to inspect the Python code that generates the tables).

Edit: BTW, sharing rank positions for tied teams/inidividuals is what is currently being done within a challenge.

Cleanup Status:
Nov 27: 9854 tasks outstanding; 4781 affecting individual (259) scoring positions; 1969 affecting team (46) scoring positions.
Nov 28: 8739 tasks outstanding; 3998 affecting individual (250) scoring positions; 1715 affecting team (43) scoring positions.
____________

Time flies like an arrow. Fruit flies like a banana.

Cleanup Status:
Nov 27: 9854 tasks outstanding; 4781 affecting individual (259) scoring positions; 1969 affecting team (46) scoring positions.
Nov 28: 8739 tasks outstanding; 3998 affecting individual (250) scoring positions; 1715 affecting team (43) scoring positions.
Nov 29: 8108 tasks outstanding; 3628 affecting individual (242) scoring positions; 1553 affecting team (42) scoring positions.
Nov 30: 7571 tasks outstanding; 3247 affecting individual (237) scoring positions; 1423 affecting team (41) scoring positions.
Dec 1: 3612 tasks outstanding; 970 affecting individual (165) scoring positions; 457 affecting team (25) scoring positions.
Dec 2: 1997 tasks outstanding; 316 affecting individual (97) scoring positions; 209 affecting team (14) scoring positions.
Dec 3: 1521 tasks outstanding; 211 affecting individual (78) scoring positions; 142 affecting team (12) scoring positions.
Dec 4: 778 tasks outstanding; 83 affecting individual (50) scoring positions; 8 affecting team (5) scoring positions.
Dec 5: 609 tasks outstanding; 55 affecting individual (37) scoring positions; 6 affecting team (4) scoring positions.
Dec 6: 551 tasks outstanding; 46 affecting individual (31) scoring positions; 6 affecting team (4) scoring positions.
Dec 7: 475 tasks outstanding; 42 affecting individual (28) scoring positions; 6 affecting team (4) scoring positions.
Dec 8: 391 tasks outstanding; 32 affecting individual (21) scoring positions; 5 affecting team (3) scoring positions.
Dec 9: 264 tasks outstanding; 24 affecting individual (17) scoring positions; 5 affecting team (3) scoring positions.
Dec 10: 110 tasks outstanding; 5 affecting individual (4) scoring positions; 0 affecting team (0) scoring positions.
____________

Time flies like an arrow. Fruit flies like a banana.

The results are final!

During these 3 short days, we completed almost 300,000 tasks. We found 202 new AP sequences, including one AP26! The challenge boosted the project's average output to 13 times typical.

135 teams and 582 individuals participated in the Challenge - the most we've had in a while!

Top Three Individuals:
1. Galumpkis
2. MiHost
3. vaughan

Top Three Teams:
1. TeAm AnandTech
2. AMD Users
3. Antarctic Crunchers

Thank you again to everyone. We really appreciate your participation and hope you had fun!
____________

Time flies like an arrow. Fruit flies like a banana.