20101124, 23:14  #34 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
2^{5}×3×101 Posts 
Any known factor can be "found" with TF.
Hint: check the structure of the TF savefile (it is only a few bytes), check the order of modular loops (this is a bit convoluted, TF is not sequential in every bitlevel), set up the good starting values and start TF with properly prepared savefile. (Another option is to recompile Prime95 to finetune it for this task.) If the machine was reliable, then try it again; you can even save some time by using Pminus1=1,2,23355961,1,500,60000000 in worktodo.txt. It appears to work fine here. In that range, however, the numbers appear to have been tested to about B1=280000, B2=6370000, which is not enough to find this factor. 
20101125, 01:54  #35  
Nov 2010
2_{10} Posts 
Heh, OK. Naturally you can 'find' it with just one modular exponentiation.
Quote:
I'll see if I can repeat it, but that machine's motherboard died in 2008, and I don't know for sure which version of Prime95 I used. Now here's a case where we'd like to set the stage 2 starting point... 

20101126, 07:15  #36 
Sep 2010
Scandinavia
3·5·41 Posts 
M2135957 has a factor: 1540376824575416172080436777449
101bit k=2^2*17*239*751*1399*6971*25033*121013 P1 
20101209, 18:13  #37 
"CharlesgubOB"
Jul 2009
Germany
2×313 Posts 
M79804321 has a factor: 50705092580156382209
recent result from me, found at December, 8th 2010 Last fiddled with by moebius on 20101209 at 18:30 
20101209, 18:33  #38 
Dec 2007
Cleves, Germany
1022_{8} Posts 
Still hanging around with Miss February, are we?

20101209, 19:05  #39 
"CharlesgubOB"
Jul 2009
Germany
2·313 Posts 

20101209, 22:08  #40 
May 2010
3^{2}×7 Posts 
Add 2 more ECM factors to the list:
2 ECM factors found a day apart, after 2 months of unsuccessful attempts
M5457773 121234416604163371249241 M5456387 168049675942742879743 
20101212, 18:02  #41 
Sep 2006
Odenton, MD, USA
2^{2}·41 Posts 
Here are some of my recent finds, all found with P1:
M5568817 has a factor: 2580875798900949823169201 M5575387 has a factor: 24002502239318494727833 M5576897 has a factor: 2685038897114218470311471 M5579477 has a factor: 264051970555252442377 M5976967 has a factor: 200673846075753516727 M5975051 has a factor: 21173271365286672676124929 M5910731 has a factor: 41919405374519888959 
20101213, 00:31  #42  
Sep 2010
Annapolis, MD, USA
3^{3}·7 Posts 
Quote:
How does one perform P1 on such "small" numbers? Is there an option, is it done by manual assignment, or do you simply select arbitrary numbers? (It is still amusing to me to consider a number like M5568817 to be small.) 

20101213, 01:20  #43 
Sep 2006
Odenton, MD, USA
2^{2}×41 Posts 
KinkKurly,
The weather has been so lovely, I've been inside all day except I just had to pick up my son from work. At least it too warm to snow.... Ooooops, having flashbacks to last Feb. As for the assigments, I do a "Factoring limits" query the based on the exponent range, pick the ones with small B1 & B2 bounds, created a worktodo.txt and then register them via the server. Been doing this off and on for over a year now. 
20101218, 02:52  #44  
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}·3·641 Posts 
Quote:
Your brief explanation assumes that the reader knows how to avoid interfering with others' assignments. Please, instead, refer folks to this LMH sticky thread: "How to LMH using Prime95 v25.8 and PrimeNet v5" at http://mersenneforum.org/showthread.php?t=11308 and emphasize the importance of step 8. Quote:
Please see this LMH sticky thread: "How to LMH using Prime95 v25.8 and PrimeNet v5" at http://mersenneforum.org/showthread.php?t=11308 It explains how to obtain assignments outside the standard PrimeNet process, while making sure there's no interference or poaching. Do not skip step 8 of Uncwilly's procedure  it is crucial to preventing accidental overlapping with other people's assignments! But do use the standard manual PrimeNet assignment system for exponents in ranges PrimeNet is allowing to be handed out. IOW, first try to get manual assignment from PrimeNet for your range of interest, then if PrimeNet isn't handing out that range, release any unwanted exponents it did assign you, then go to carefully follow Uncwilly's procedure. Last fiddled with by cheesehead on 20101218 at 03:06 

Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Congruent prime numbers that preserves the modulo as the largest prime factor of the sum  Hugo1177  Miscellaneous Math  5  20210211 07:40 
Factorization factory  Branger  Factoring  15  20190905 15:03 
A fond farewell  rogue  Lounge  10  20081121 05:25 
Berry paradox without paradox.  victor  Puzzles  7  20080408 22:34 