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-   -   New Fermat factors (https://www.mersenneforum.org/showthread.php?t=15449)

 JeppeSN 2020-01-25 18:03

[QUOTE=Dr Sardonicus;535944]For the remaining value, 6*2^5523860 + 1, I didn't look far enough to find any factors, but I didn't look all that far. Has (as I suspect) someone already found a factor by trial division, or otherwise shown it to be composite?[/QUOTE]

Yes, your number 3*2^5523861 + 1 is composite, because PrimeGrid has established the primality status of all numbers 3*2^n ± 1 for n up to over 15.5 million, see [URL="https://www.primegrid.com/stats_321_llr.php"]their page stats_321_llr[/URL]. We do not have access to their data, but if we ask them, they can maybe tell us if this candidate was eliminated during sieving (they may have the prime factor then) or during primality testing and double checking (they may have the residue then). However, I guess it is of limited interest. /JeppeSN

 Dr Sardonicus 2020-01-27 14:30

3*2^5523861 + 1 is definitely composite. From the [url=http://www.prothsearch.com/riesel1.html]List of primes k*2[sup]n[/sup] + 1 for k < 300[/url] we have for k = 3,
[quote]3 1, 2, 5, 6, 8, 12, 18, 30, 36, [b]41[/b], 66, 189, 201, [b]209[/b], 276, 353, 408, 438, 534, 2208, 2816, 3168, 3189, 3912, 20909, 34350, 42294, 42665, 44685, 48150, 54792, 55182, 59973, 80190, [b]157169[/b], [b]213321[/b], [b]303093[/b], 362765, [b]382449[/b], 709968, 801978, 916773, 1832496, [b]2145353[/b], 2291610, [b]2478785[/b], 5082306, 7033641, 10829346 [14884000][/quote](The exponents in bold give factors of Fermat numbers.)

 ET_ 2020-05-25 12:37

New fermat factor!

May 22nd, 2020
New Fermat factor from FermatSearch!
47893 . 2[SUP]134998[/SUP]+1 is a Factor of F[SUB]134995[/SUB]!!!
Gary Gostin discovered the second Fermat factor of this year!
This was discovered on an AMD EPYC 7702P based server running a new version of pmfs that incorporates George Woltman's gwnum library.
Congratulations to Gary from FermatSearch, for his 83rd factor, we now have 352 Fermat factors known!

 mathwiz 2020-05-25 13:36

[QUOTE=ET_;546396]May 22nd, 2020
New Fermat factor from FermatSearch!
47893 . 2[SUP]134998[/SUP]+1 is a Factor of F[SUB]134995[/SUB]!!!
Gary Gostin discovered the second Fermat factor of this year!
This was discovered on an AMD EPYC 7702P based server running a new version of pmfs that incorporates George Woltman's gwnum library.
Congratulations to Gary from FermatSearch, for his 83rd factor, we now have 352 Fermat factors known![/QUOTE]

Awesome, congrats!!

Is the new pmfs version available somewhere, either as source or a compiled Linux binary?

 ET_ 2020-05-25 14:09

[QUOTE=mathwiz;546398]Awesome, congrats!!

Is the new pmfs version available somewhere, either as source or a compiled Linux binary?[/QUOTE]

Not at the moment. It's still in development.
No plans for a public release, either.

 ET_ 2020-06-30 10:20

New Fermat Factor!

[code]
Hello Luigi,

I would like to report the following new Fermat factor:

171,369,935 * 2^11077 + 1 divides F11075

This was discovered today (June 29) running pmfs on an HPE Superdome X system.
[/code]

Congratulations Gary!!!

Please note that due to a migration to upgrade the webserver I had to schedule to grant power, space and bandwidth to you all, migration happening between today and tomorrow, the FermatSearch.org site update will be delayed.

Luigi

 ryanp 2020-10-04 23:51

From my recent Proth prime:

[CODE]7*2^18233956+1 is a Factor of F18233954!!!! (163569.267086 seconds)[/CODE]

 Gary 2020-10-05 03:17

[QUOTE=ryanp;558898]From my recent Proth prime:

[CODE]7*2^18233956+1 is a Factor of F18233954!!!! (163569.267086 seconds)[/CODE][/QUOTE]

Congrats Ryan!!!!!!!!!! That is one HUGE factor. :w00t:

 carpetpool 2020-10-05 04:27

[QUOTE=ryanp;558898]From my recent Proth prime:

[CODE]7*2^18233956+1 is a Factor of F18233954!!!! (163569.267086 seconds)[/CODE][/QUOTE]

Congrats on a World Record Fermat Divisor!

:bounce wave:

[SUB]PrimeGrid has held the record for many years up until now...[/SUB]

Way to go!

 ET_ 2020-10-05 09:45

[QUOTE=ryanp;558898]From my recent Proth prime:

[CODE]7*2^18233956+1 is a Factor of F18233954!!!! (163569.267086 seconds)[/CODE][/QUOTE]

Congratulations! Did you find it on ProthSearch?
Any more infos related to the computing system and the program you used (and its maintainer)?

Luigi
---

 Dr Sardonicus 2020-10-05 11:02

[QUOTE=ryanp;558898]From my recent Proth prime:

[CODE]7*2^18233956+1 is a Factor of F18233954!!!! (163569.267086 seconds)[/CODE][/QUOTE]
Great -- another proof that the number is prime! Congratulations!

:tu:

:bow wave:

:toot:

:beer:

:party:

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