New Fermat factors

[henryzz]

Originally Posted by petrw1

[Dec 29 13:46][Dec 29 14:42] F13 curve 1 stage 2 at prime 24254611921 [93.219%]. Time: 3371704.819 ms.
[Dec 29 14:51] Stage 2 complete. 2149490141 transforms, 2 modular inverses. Time: 503716.573 ms.
[Dec 29 14:51] Stage 2 GCD complete. Time: 6.245 ms.
[Dec 29 14:51] F13 has a factor: 26020122470308761124295813561435868695786791305217

No it is three smallest factors multiplied together.
http://factordb.com/index.php?query=F13
http://factordb.com/index.php?query=...95786791305217

[WraithX]

Originally Posted by petrw1

[Dec 29 13:46][Dec 29 14:42] F13 curve 1 stage 2 at prime 24254611921 [93.219%]. Time: 3371704.819 ms.
[Dec 29 14:51] Stage 2 complete. 2149490141 transforms, 2 modular inverses. Time: 503716.573 ms.
[Dec 29 14:51] Stage 2 GCD complete. Time: 6.245 ms.
[Dec 29 14:51] F13 has a factor: 26020122470308761124295813561435868695786791305217

Unfortunately no, this is not a new factor. It is composite and factors into:
2710954639361 * 2663848877152141313 * 3603109844542291969
Which are the first 3 (of 4) known factors for F13.

You can use yafu or pari/gp to try to factor the number, and then you can check Fermat factor status here: http://www.prothsearch.net/fermat.html

[ET_]

I'll be AFK from Jan. 2nd to Jan. 9th.

If you (DoubleMersennes and FermatSearch) have ranges that will end or want to reserve some mor ranges over that period of time, you can reserve them up to the night of 1st.

And feel free to discover new factors when I'm away!

Luigi

[f11ksx]

I have run GMP-ECM and i have this results:

Found factor 19009615*2^14+1 of 2^(2^11)+1
Found factor 182126139*2^14+1 of 2^(2^12)+1
Found factor 446369595*2^14+1 of 2^(2^12)+1
Found factor 12657656493*2^17+1 of 2^(2^12)+1

Is it useful or already know?

[Ralf Recker]

Originally Posted by f11ksx

I have run GMP-ECM and i have this results:

Found factor 19009615*2^14+1 of 2^(2^11)+1
Found factor 182126139*2^14+1 of 2^(2^12)+1
Found factor 446369595*2^14+1 of 2^(2^12)+1
Found factor 12657656493*2^17+1 of 2^(2^12)+1

Is it useful or already know?

http://www.prothsearch.net/fermat.html

[ET_]

March 14th, 2014
New Fermat factor from FermatSearch!
209161375 . 2⁴²⁶²+1 is a Factor of F₄₂₆₀!!!
Takahiro Nohara found his tenth Fermat factor using NewPGen 2.82 for sieve, PFGW 3.7.5 for PRP and GFN divisibility testing for this discovery.
Congratulations to Takahiro Nohara from FermatSearch, for the first factor of the year!

Luigi

[Batalov]

Phew! Almost nine months without a factor, a voila - a beautiful full-term baby was born. Cigars all around!

[Batalov]

Originally Posted by f11ksx

I have run GMP-ECM and i have this results:

Found factor 19009615*2^14+1 of 2^(2^11)+1
Found factor 182126139*2^14+1 of 2^(2^12)+1
Found factor 446369595*2^14+1 of 2^(2^12)+1
Found factor 12657656493*2^17+1 of 2^(2^12)+1

Is it useful or already know?

Khm... These are not prime, but are products of two known prime factors each:

19009615*2^14+1 = (39*2^13+1)*(119*2^13+1)
These are known for 115 years.

182126139*2^14+1 = (7*2^14+1)*(397*2^16+1)
446369595*2^14+1 = (7*2^14+1)*(973*2^16+1)
12657656493*2^17+1 = (397*2^16+1)*(973*2^16+1)
These are known for 111 years.

[f11ksx]

Thank you Sergey

[R.D. Silverman]

Originally Posted by f11ksx

Thank you Sergey

Next time you might want to consider a Google search BEFORE
you waste computing time.

[ET_]

May 26th, 2014
The Number of the Beast is not prime!
217924552867 . 2^668+1 is a Factor of F666!!!
Roman Maznichenko found his fifth Fermat factor using an Intel (Haswell) i5-4670K@4000GHz and Feromant, a program he wrote, for this discovery.
Congratulations to Roman from FermatSearch, for the second factor of the year!

Luigi