20090226, 13:52  #1 
Jun 2003
491_{16} Posts 
P1 Stage 1 factor
M40969891has a factor: 81079117666989161
But why wasn't it found during TF? 
20090226, 14:33  #2 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
On a Core 2 under Linux, version 25.8 finds it, but version 24.14 doesnt (with FactorOverride to stop at 2^60):
Code:
Mersenne number primality test program version 24.14 Starting factoring M40969891 to 2^60 [Feb 26 15:23] Factoring M40969891 to 2^57 is 55.81% complete. Time: 25.990 sec. [Feb 26 15:23] Factoring M40969891 to 2^58 is 27.90% complete. Time: 16.751 sec. [Feb 26 15:24] Factoring M40969891 to 2^58 is 55.81% complete. Time: 8.761 sec. [Feb 26 15:24] Factoring M40969891 to 2^58 is 83.70% complete. Time: 7.622 sec. [Feb 26 15:24] Factoring M40969891 to 2^59 is 13.95% complete. Time: 12.225 sec. [Feb 26 15:24] Factoring M40969891 to 2^59 is 27.90% complete. Time: 7.419 sec. [Feb 26 15:24] Factoring M40969891 to 2^59 is 41.85% complete. Time: 7.084 sec. [Feb 26 15:24] Factoring M40969891 to 2^59 is 55.81% complete. Time: 7.256 sec. [Feb 26 15:24] Factoring M40969891 to 2^59 is 69.75% complete. Time: 7.460 sec. [Feb 26 15:24] Factoring M40969891 to 2^59 is 83.70% complete. Time: 7.081 sec. [Feb 26 15:25] Factoring M40969891 to 2^59 is 97.66% complete. Time: 7.069 sec. [Feb 26 15:25] Factoring M40969891 to 2^60 is 6.98% complete. Time: 8.604 sec. [Feb 26 15:25] Factoring M40969891 to 2^60 is 13.96% complete. Time: 7.153 sec. [Feb 26 15:25] Factoring M40969891 to 2^60 is 20.95% complete. Time: 7.670 sec. [Feb 26 15:25] Factoring M40969891 to 2^60 is 27.93% complete. Time: 7.726 sec. [Feb 26 15:25] Factoring M40969891 to 2^60 is 34.91% complete. Time: 8.037 sec. [Feb 26 15:25] Factoring M40969891 to 2^60 is 41.90% complete. Time: 7.452 sec. [Feb 26 15:25] Factoring M40969891 to 2^60 is 48.88% complete. Time: 7.852 sec. [Feb 26 15:26] Factoring M40969891 to 2^60 is 55.86% complete. Time: 6.967 sec. [Feb 26 15:26] Factoring M40969891 to 2^60 is 62.84% complete. Time: 7.219 sec. [Feb 26 15:26] Factoring M40969891 to 2^60 is 69.83% complete. Time: 7.396 sec. [Feb 26 15:26] Factoring M40969891 to 2^60 is 76.81% complete. Time: 7.533 sec. [Feb 26 15:26] Factoring M40969891 to 2^60 is 83.80% complete. Time: 7.691 sec. [Feb 26 15:26] Factoring M40969891 to 2^60 is 90.78% complete. Time: 6.916 sec. [Feb 26 15:26] Factoring M40969891 to 2^60 is 97.76% complete. Time: 7.497 sec. M40969891 no factor to 2^60, Wc2: 895110A9 Edit: Version 24.14 on a P4 didn't find it, either. They both may have run the same code path, though, then this would not be surprising. Alex Last fiddled with by akruppa on 20090226 at 16:03 
20090226, 18:34  #3 
Just call me Henry
"David"
Sep 2007
Cambridge (GMT/BST)
2^{2}×1,481 Posts 
i am currently running on windows on a core 2 32bit
i will be able to do a windows athlon 64 32bit run tomorrow morning edit: no factor found on the core 2 with 24.14 edit2: ran on the athlon 64 and the same result no factor with 24.14 edit3: even more worrying no factor was found for 25.8 on either pc before you ask i am certain that i typed it in correctly as i copied it and double checked it edit4: will i ever stop editing? i have just attached the worktodo.txt i used for 25.8 edit5: no factor5 has just found the factor for me Last fiddled with by henryzz on 20090226 at 19:18 
20090226, 21:11  #4 
Sep 2006
Odenton, MD, USA
A4_{16} Posts 
I tried both v25.8 build 5 and v25.9 build 3 on a P4 32bit windows box and neither one found the factor
Last fiddled with by harlee on 20090226 at 21:13 
20090226, 21:50  #5 
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}×3×641 Posts 
v25.8, Windows XP SP3, Pentium D
Factor=40969891,40,0 M40969891 no factor from 2^40 to 2^59 M40969891 no factor from 2^59 to 2^60 M40969891 no factor from 2^60 to 2^61 ... Last fiddled with by cheesehead on 20090226 at 21:58 
20090226, 22:40  #6 
May 2008
3·5·73 Posts 
25.9.8 x86_64 on Linux x86_64 Core 2 Duo finds the factor:
Code:
[Main thread Feb 26 16:38] Starting worker. [Work thread Feb 26 16:38] Worker starting [Work thread Feb 26 16:38] Setting affinity to run worker on any logical CPU. [Work thread Feb 26 16:38] Starting trial factoring of M40969891 to 2^66 [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^50. [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^51. [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^52. [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^53. [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^54. [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^55. [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^56. [Work thread Feb 26 16:38] Trial factoring M40969891 to 2^57. [Work thread Feb 26 16:38] M40969891 has a factor: 81079117666989161 [Work thread Feb 26 16:38] No work to do at the present time. Waiting. 
20090226, 22:45  #7 
"Jacob"
Sep 2006
Brussels, Belgium
2·3^{2}·97 Posts 
I tried on a quad Core2 under Windows and only the 64 bit versions (24.14 and 25.9.3) of Prime95 found the factor.
Prime95 25.9.3 32 bits does not find it. Jacob Last fiddled with by S485122 on 20090226 at 22:46 
20090226, 22:49  #8 
May 2008
1095_{10} Posts 
But 25.9.2 i386 does not:
Code:
[Main thread Feb 26 16:49] Starting worker. [Work thread Feb 26 16:49] Worker starting [Work thread Feb 26 16:49] Setting affinity to run worker on any logical CPU. [Work thread Feb 26 16:49] Starting trial factoring of M40969891 to 2^66 [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^50. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^51. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^52. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^53. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^54. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^55. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^56. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^57. [Work thread Feb 26 16:49] Trial factoring M40969891 to 2^58. ^C[Main thread Feb 26 16:49] Stopping all worker threads. [Work thread Feb 26 16:49] Worker stopped. [Main thread Feb 26 16:49] Execution halted. [Main thread Feb 26 16:49] Choose Test/Continue to restart. 
20090226, 22:52  #9 
May 2008
3·5·73 Posts 

20090226, 22:57  #10 
Account Deleted
"Tim Sorbera"
Aug 2006
San Antonio, TX USA
10AD_{16} Posts 
32bit 25.9.2 on Windows.
Code:
M40969891 no factor to 2^59, Wd1: 895110A9 
20090227, 03:01  #11 
Sep 2006
Odenton, MD, USA
2^{2}×41 Posts 
I even tried v24.13 and v24.14 on a P4 32bit Windows system and still no factors found.

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