mersenneforum.org Didn't even find a useless factor of an uninteresting number! Take that!
 Register FAQ Search Today's Posts Mark Forums Read

 2014-06-15, 03:23 #1 storflyt32   Feb 2013 2·229 Posts Didn't even find a useless factor of an uninteresting number! Take that! 10^444031*9-1 has a known factor 66666323. Apparently there is a factor 114851129 of (10^444031*9-1)/66666323 as well. It took quite a bit of time finding this small factor using Yafu's ECM command and for now I did not redirect the output to any file. Therefore the whole process including the comparison of the numbers became more or less manual between three different DOS window boxes. Last fiddled with by storflyt32 on 2014-06-15 at 03:25 Reason: Better wording.
 2014-06-15, 04:37 #2 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2·3·5·313 Posts It takes only a few seconds to find by this (very slow) script: Code: > gp -q ? p=66666321; ? while(1,p=nextprime(p+1);if(Mod(10,p)^444031*9==1, print(p))) 66666323 114851129
 2014-10-08, 01:39 #3 storflyt32   Feb 2013 2×229 Posts A question for you. This number: http://factordb.com/index.php?query=2%5E4096%2B1 The composite number there (a C1133) has not been factored. I know that there have been made several attempts, but for now without success. Another number more indirectly related to this number is being found here. http://factordb.com/index.php?query=...53262018919671 Perhaps I should rather tell you that I do have a factor for this number lying around. It is a somewhat larger factor, a P34, to be more precise. I will need to carry out the factorization once again, because I have lost it. For now I only do have the mentioned factor available.
 2014-10-08, 02:07 #4 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2·3·5·313 Posts It is not related. It is a cofactor of (2^4096+1)/25860116183332395113497853167940236083358054\ 650286886725246241569916604094012679963198712829716480001-2 not of 2^4096+1
 2014-10-12, 06:16 #5 storflyt32   Feb 2013 2×229 Posts ans = 10906594903029791068395400811884464627409515459009973450004302442452725255227 P35 = 62611614700115894971255725399191227 P42 = 174194435892891975029270196982744708432001
 2014-10-12, 08:58 #6 bloodIce     Feb 2010 Sweden 173 Posts Very long factor(s), good catch. Do you plan to report them to mersenne.org ?
 2014-10-13, 14:52 #7 storflyt32   Feb 2013 2×229 Posts Thanks! Anyway, I notice a problem with the Yafu factoring software. I am having a 64-bit computer, so I am using both the 32-bits and 64-bits versions of this software. Apparently the 32-bit version is returning the wrong co-factor number in the result. This has now become a very annoying feature and needs to be fixed as soon as possible. Thanks again! Last fiddled with by storflyt32 on 2014-10-13 at 14:54
 2014-10-13, 17:22 #8 VBCurtis     "Curtis" Feb 2005 Riverside, CA 3·1,579 Posts If you are reporting a bug, please list the YAFU version number, and the composite & result so someone else can try to reproduce it.
2014-10-13, 17:26   #9
Batalov

"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

2×3×5×313 Posts

Quote:
 Originally Posted by storflyt32 ans = 10906594903029791068395400811884464627409515459009973450004302442452725255227 P35 = 62611614700115894971255725399191227 P42 = 174194435892891975029270196982744708432001
What is this number, anyway?

 2014-10-14, 13:10 #10 storflyt32   Feb 2013 2·229 Posts ans = 5687625641025641025641025641025641025641025641025641025641025641025641025641 P33 = 213843479182611070647190753814939 P44 = 26597143213184949293331777384754973697286219
 2014-10-14, 23:33 #11 VictordeHolland     "Victor de Hollander" Aug 2011 the Netherlands 23×3×72 Posts I *guess* he is factoring the "smallest composite without known factors" from the factordb, those are also 76 digits.

 Similar Threads Thread Thread Starter Forum Replies Last Post wwf Factoring 26 2013-09-30 04:24 Arkadiusz Software 7 2013-02-18 12:43 RedGolpe Factoring 4 2007-03-23 15:24 geoff Factoring 5 2004-09-29 20:14 chrow Factoring 5 2004-02-19 10:15

All times are UTC. The time now is 02:29.

Mon Apr 19 02:29:12 UTC 2021 up 10 days, 21:10, 0 users, load averages: 1.49, 1.79, 1.86