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 Kosmaj 2013-05-15 07:52

Congrats to Bishop (L3514) and Primegrid on new largest Fermat divisor:

57*2^2747499+1 (827082 digits)

As a reminder, a prime of form k*2^n+1 can be Fermat divisor with probability 1/k regardless of n.

BTW, the legendary record Fermat divisor found by Cosgrave in 2003 (3*2^2478785+1) is now 3rd!

 literka 2013-05-15 13:36

[QUOTE=Kosmaj;340532]Congrats to Bishop (L3514) and Primegrid on new largest Fermat divisor:

57*2^2747499+1 (827082 digits)

As a reminder, a prime of form k*2^n+1 can be Fermat divisor with probability 1/k regardless of n.

BTW, the legendary record Fermat divisor found by Cosgrave in 2003 (3*2^2478785+1) is now 3rd![/QUOTE]

This is not listed on [url]www.prothsearch.net/fermat.html[/url] yet.
Such results surprise me, since I expect that simple multiplication of 2 numbers of this size should last years. There must be technique I am not aware of.
It is not written what Fermat number has this divisor, but for sure we even cannot imagine the size of this Fermat number.

 Kosmaj 2013-09-09 02:24

Congrats to Batalov on nice primes based on known Mersenne primes:

507568*(2^1398269-1)+1, 420927 digits
374568*(2^3021377-1)+1, 909531 digits

BTW, there seems to be a way to include the helper with your submission,
so that the verification on CC's server is done using the helper. See here:
[url]http://primes.utm.edu/primes/page.php?id=115087[/url]

 Batalov 2013-09-17 18:20

Well, [URL="http://primes.utm.edu/primes/page.php?id=115540"]here's a prime[/URL] that is easy to write down.
It is a "one", followed by 1,059,002 "nines".

Full size posters are available from primes'Я'us.ru ;-)

 pepi37 2013-09-17 19:01

Congratulations!!!!

 Batalov 2013-10-10 01:05

There's a large Riesel Problem prime in verification.
It will come in [URL="http://primes.utm.edu/primes/page.php?id=115858"]in position #23[/URL]. Congrats to PGrid!

And a day later, [URL="http://primes.utm.edu/primes/page.php?id=115875"]one more[/URL], also in position #23. ;-)

 Kosmaj 2013-10-12 01:42

Yeah, one more:
[URL="http://primes.utm.edu/primes/page.php?id=115875"]304207*2^6643565-1[/URL] (1999918 digits)

Only 82 digits shy of 2M digits!
That's that guy Randy who joined prime search in June this year and already has more than 500 primes in Top-5000, is first by number, and with this one will probably become 11th by score. Amazing computing power! :shock:

 pinhodecarlos 2013-11-29 10:30

Batalov found [url]http://primes.utm.edu/primes/page.php?id=116472[/url]. Congratulations!

 Kosmaj 2013-11-29 13:42

Yeah, indeed congrats to Batalov.

And a great chance for the new Fermat divisor record!

 pinhodecarlos 2013-12-28 02:11

[url]http://primes.utm.edu/primes/page.php?id=116744[/url]

 Batalov 2014-01-17 20:00

A huge [URL="http://primes.utm.edu/primes/page.php?id=116922"]Proth prime[/URL] was found by Tang&PrimeGrid.
I wonder if they are [I]still[/I] in the process of running the xGF tests.

(They should have parallelized them into a lot of "foreach i (2 3 5 6 10 12) pfgw -gos\$i -lgos\$i.log p" processes. For a plainly run "pfgw -gxo p" result, they may wait for days/weeks. It is also possible to write a parallel implementation, based on the PRP test in Prime95: just a few lines need to be changed and then a GF-divisor test could have been be run threaded, i.e. much faster still.)

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