20100328, 02:07  #12 
P90 years forever!
Aug 2002
Yeehaw, FL
7532_{10} Posts 
So this is a GMPECM success, not a GIMPS success. Congrats also to akruppa who put a lot of work into a specialized stage 2 for Fermat numbers.
Please email me your curve counts when you are done so that the ECM tables can be updated. 
20100328, 02:08  #13 
Bemusing Prompter
"Danny"
Dec 2002
California
2·3^{2}·7·19 Posts 

20100328, 07:20  #14 
Dec 2007
Cleves, Germany
2×5×53 Posts 
It's about time for a Fermat subforum...

20100328, 08:22  #15 
"Phil"
Sep 2002
Tracktown, U.S.A.
3·373 Posts 
Congratulations, Mike, and congratulations, Alex! I am truly astounded  no ECM factors of Fermat numbers for over a decade, and then, four within nine months, with the last three within two months! I notice a trend of these showing up a bit on the "late" side, i.e., after the recommended number of curves at the given digit level have already been run, except for the factor of F14. Probably just a coincidence, but it certainly shows that persistence pays off.

20100328, 12:31  #16 
Mar 2004
Belgium
349_{16} Posts 
Do you guys take into account the factors found @ http://www.fermatsearch.org/news.html ?
Regards C. 
20100328, 13:26  #17 
Noodles
"Mr. Tuch"
Dec 2007
Chennai, India
3×419 Posts 
In this website page:
http://prothsearch.net/fermat.html 12 1187 2010 Different anonymous provers Shouldn't the number of digits be 1133? It is updated correctly with F_{12} = 114689 · 26017793 · 63766529 · 190274191361 · 1256132134125569 · 568630647535356955169033410940867804839360742060818433 · C1133 Then, why within that Composite cofactors of Fermat numbers F_{m} section, F14 is left over? Because of the fact that it is too trivial to prove that by using the Fermat's Little Theorem? Similarly, much easier is the case for F12? Either F12 should be left over within that section or that number of digits should be correctly updated up to be 1133, right then? Thus, it should not be incorrectly written up as 1187 digits at all, even especially with the year of proving that the cofactor of F12 is composite as 2010, at all. thus Last fiddled with by Raman on 20100328 at 13:28 
20100328, 13:47  #18 
"Tapio Rajala"
Feb 2010
Finland
100111011_{2} Posts 
Congratulations to Michael on this amazing find!
I have recently spent a large portion of my computer resources on F_{12} as well (over 1800 curves with B1=260M) and reading about this new factor truly made me happy! The recent boom in finding factors of "small" Fermat numbers is almost mind boggling. 
20100328, 22:05  #19 
Jul 2009
Hobart, Australia
11 Posts 
A curious entry in results file prime95
does this relate to a factor of F21 or F12 or has my computer had some bizzare error.
[Mon Mar 29 04:35:02 2010] UID: Buckle/NetworkMan, F21 completed 3 ECM curves, B1=3000000, B2=300000000, Wd4: 244338EA, AID: 3DF716298AB5D181BA2E552234F828AC ECM found a factor in curve #1, stage #1 Sigma=2333235840349316, B1=3000000, B2=300000000. UID: Buckle/NetworkMan, F12 has a factor: 396532184444319600058061052745788134326273, AID: 3DF716298AB5D181BA2E552234F828AC 
20100328, 22:20  #20 
Jun 2003
2^{3}·5·127 Posts 
396532184444319600058061052745788134326273 = 26017793 × 63766529 × 190274191361 × 1256132134125569
These are all known factors. See http://www.factordb.com/search.php?query=F12 
20100329, 05:16  #21 
"Phil"
Sep 2002
Tracktown, U.S.A.
1119_{10} Posts 
A correction to my previous post: The recent factor of F22 was not "late", but right on time. The factors of F12 and F19 seem to have shown up a bit late.

20100411, 12:42  #22 
Mar 2010
2^{6}×3 Posts 
Nice result. Congratulations.
