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

pinhodecarlos 2012-02-07 19:15

[QUOTE=rogue;288555]PrimeGrid finds another one:

131*2^1494099+1 Divides F(1494096)[/QUOTE]

It was found by Rob Derrera and not by Primegrid. Why do you insist the fermat factors were found by Primegrid?

rogue 2012-02-07 19:43

[QUOTE=pinhodecarlos;288562]It was found by Rob Derrera and not by Primegrid. Why do you insist the fermat factors were found by Primegrid?[/QUOTE]

I would prefer that you took a more civil tone. I could have specified that he found it while working on PrimeGrid's Proth Prime Search project, but to indicate that he found it without help from PrimeGrid would not be correct either.

As I understand how the project works, his computer found the prime, but PrimeGrid runs the Fermat divisibility test on the prime. Fermat divisibility testing is done by pfgw and there is no support for pfgw in BOINC.

pinhodecarlos 2012-02-07 19:49

[QUOTE=rogue;288564]I would prefer that you took a more civil tone. [/QUOTE]
I expect the same for you too.

[QUOTE=rogue;288564]
I could have specified that he found it while working on PrimeGrid's Proth Prime Search project, but to indicate that he found it without help from PrimeGrid would not be correct either.

As I understand how the project works, his computer found the prime, but PrimeGrid runs the Fermat divisibility test on the prime. Fermat divisibility testing is done by pfgw and there is no support for pfgw in BOINC.[/QUOTE]

So it was his machine who found it and he his a member of Primegrid...I see...

rajula 2012-02-08 06:24

[QUOTE=pinhodecarlos;288562]It was found by Rob Derrera and not by Primegrid. Why do you insist the fermat factors were found by Primegrid?[/QUOTE]

Saying that it was "found by Primegrid" is also the easiest short way of providing a large amount of information and source for it. If Derrera was to be mentined, how could have rogue left out the information on programs (or main programmers) and on the sieving effort?

Saying that it was found by Primegrid tells you exactly where to find the information. It is also factually correct. (I agree with you that) the combination "main contributor to the individual test" + "project name" would have been nicer. Still, if one is to drop one of those, it should be the first one as the second one gives it easily.

Also, saying that "the factor was found by Rob Derrera and not by Primegrid" is simply wrong and even insulting to the people involved in the background work.

jmblazek 2012-02-10 20:19

[QUOTE=rogue;288564]As I understand how the project works, his computer found the prime, but PrimeGrid runs the Fermat divisibility test on the prime. Fermat divisibility testing is done by pfgw and there is no support for pfgw in BOINC.[/QUOTE]
This is correct. The server performs the Fermat divisibility test and it uses pfgw.

Maybe a simple link to the [URL="http://www.primegrid.com/download/PPS-F1494096.pdf"]official announcement[/URL] would suffice. It credits the project and its founders, the prime finder and host, the verifier and host, the software and its developers, and the thousands of others who participated in helping reach this discovery. However, a quick search at the Prime Pages for [URL="http://primes.utm.edu/primes/page.php?id=104247"]131*2^1494099+1[/URL] will provide the link as well. :smile:

But then again, maybe it falls short. For instance, the following are absent from the credits:[INDENT] the manufacturers of all the hardware
the creators of the code used in the development of the programs
the "helper" software used within the programs
the server that actually ran the Fermat divisibility test
the parents who conceived all those involved
ad absurdum
...the big bang.
[/INDENT](whew)

Scratch all that. I like rajula's comment better: "Saying that it was "found by Primegrid" is also the easiest short way of providing a large amount of information and source for it."

ET_ 2012-03-11 19:44

New fermat factor found by Fermatsearch!
 
March 11, 2012
Seventh Fermat factor found by Takahiro Nohara!
238451805 . 2[sup]2608[/sup]+1 is a Factor of F[sub]2606[/sub]!!!.
The factor was discovered by Takahiro Nohara of Japan, and is the third factor of this year.
He used NewPGen.exe by Paul Jobling for sieving and OpenPFGW.exe for PRP test and xGFN divisibility test. Takahiro found his factor while testing N=2005-2999 and k=60,000,000-400,000,000 exactly on the first anniversary of the earthquake and tsunami disaster that triggered also a nuclear accident in Fukushima..
Congratulations form the team of FermatSearch!

Luigi

wreck 2012-03-29 15:19

On March 28, 2012, Andriy Sen discovered a new Fermat factor.
4785972759 · 2^954 + 1 divides F943.

rogue 2012-03-29 15:34

[QUOTE=wreck;294656]On March 28, 2012, Andriy Sen discovered a new Fermat factor.
4785972759 · 2^954 + 1 divides F943.[/QUOTE]

Cool! What software was used?

wreck 2012-03-30 10:29

[QUOTE=rogue;294660]Cool! What software was used?[/QUOTE]
The factor was discovered by Andriy Sen of Ukraine, and is the fourth factor of this year.
He used GMP-Fermat.exe on a Windows Server 2008 R2 Standard x64, Intel Core2 CPU 6600 @ 2.40 GHz to test it. Andriy found his factor while testing N=900-989 and k=4,000,000,000-5,000,000,000.

ET_ 2012-03-30 14:40

[QUOTE=wreck;294806]The factor was discovered by Andriy Sen of Ukraine, and is the fourth factor of this year.
He used GMP-Fermat.exe on a Windows Server 2008 R2 Standard x64, Intel Core2 CPU 6600 @ 2.40 GHz to test it. Andriy found his factor while testing N=900-989 and k=4,000,000,000-5,000,000,000.[/QUOTE]

Yup, and that should be the second Fermat factor found with Mark's software... :smile:

Luigi

rogue 2012-03-30 16:29

[QUOTE=ET_;294838]Yup, and that should be the second Fermat factor found with Mark's software... :smile:[/QUOTE]

I noticed that. Now I just need to find one myself.

Note that this could be a screamer app if run on a GPU. I've thought about it, but I just don't have the time necessary for it.


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