20040408, 06:45  #1 
Oct 2003
Australia, Brisbane
2×5×47 Posts 
P1 stage 2 factor
I just beat my own personal record and just found a 43 digit factor during stage 2 of p1 factoring. My previous record was 42 digits.
P1 found a factor in stage #2, B1=70000, B2=1277500. UID: dave_0273/buffy, M12215821 has a factor: 2855451057157704997579326497626590663028969 Assuming that I did the calculation correct, this is a 142 bit factor. I am interested to know if anyone has found a bigger factor using p1. Also, I was wondering if this number is prime, I highly doubt that it is though. Last fiddled with by dave_0273 on 20040408 at 07:15 
20040408, 07:38  #2 
Feb 2003
163 Posts 
Unfortunately it's not a prime :
Code:
2855451057157704997579326497626590663028969 = 896774094182730749591 * 3184136423744490284159 A list with p1 records you can find in the ECMnet pages : http://www.loria.fr/~zimmerma/records/Pminus1.html 
20040409, 02:41  #3 
Oct 2003
Australia, Brisbane
2·5·47 Posts 
I just beat my own record again. Interesting that I beat it just the next day. Anyways, here is the factor....
P1 found a factor in stage #2, B1=70000, B2=1312500. UID: dave_0273/faith, M12223199 has a factor: 264230314763760208834215981504580626343342447 It is 45 digits and weighs in at 148 bits. Could someone check for me to see if it is prime please?? Last fiddled with by dave_0273 on 20040409 at 02:47 
20040409, 02:50  #4  
Nov 2003
165_{10} Posts 
Quote:
You can check them yourself at http://www.alpertron.com.ar/ECM.HTM 

20040409, 03:01  #5 
Oct 2003
Australia, Brisbane
2×5×47 Posts 
Thanks for that link.

20040415, 16:41  #6 
Mar 2003
Melbourne
5×103 Posts 
Well done Dave, you qualify for that list.
I'm just not in the same ball park  my largest is 25digits: 3392287301461488893415377 for M13127581. But hey it's prime :) Is there a way to look up the data files to see if anyone else has anything bigger?  Craig 
20040415, 20:31  #7 
P90 years forever!
Aug 2002
Yeehaw, FL
3·5·499 Posts 
These are the 35 digit and longer factors found with prime95:
17504141 45.00 426315489966437174530195419710289226952407399 1026199 41.00 99986711862609678639226074113089334488633 14334623 39.00 563796628294674772855559264041716715663 23343809 39.00 126200820168972868753938399731010991289 15864539 37.00 5811726848289439035828246985293098183 20396191 36.00 275806877795314616777110237874197111 5480471 35.00 87590114272360866473519508282751337 13187813 35.00 63113922700063643342764849026462401 1018697 35.00 51776547638454015479754532135290881 18965599 35.00 34488602653675602192712514732427431 16026793 35.00 19929728012623917458862281965016471 20092067 35.00 13168424217984320584506969049382921 
20040415, 21:23  #8 
Feb 2003
163 Posts 
What about
6659 42.00 226211124686120782835233945344253671049543 27691 37.00 1734072082042172647364731231822850071 Both are 'smooth' enough for Prime95. (found in an old list created by Andy Steward) 
20040415, 22:02  #9 
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
10010101011001_{2} Posts 
43 and 45 would both put you on the top 10 list.

20040607, 14:50  #10 
Oct 2003
Australia, Brisbane
470_{10} Posts 
It doesn't beat my personal best, but here is a 43 digit factor
UID: dave_0273/buffy, M12889889 has a factor: 2975472867644373392513490171544511832022967 Unfortunately, it isn't prime 2975472867644373392513490171544511832022967 = 26296325190058 952183 x 113151660779173033002049 Still, I thought that it was worth mentioning. It is a 142 bit factor. 
20040607, 21:27  #11  
Banned
"Luigi"
Aug 2002
Team Italia
4,813 Posts 
Quote:
Did those numbers already have their LL test (I guess so)? Luigi 

Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
P1 Stage 1 factor  Mr. P1  Software  25  20090309 18:08 
Stage 1 with mprime/prime95, stage 2 with GMPECM  D. B. Staple  Factoring  2  20071214 00:21 
Need help to run stage 1 and stage 2 separately  jasong  GMPECM  9  20071025 22:32 
Stage 1 and stage 2 tests missing  Matthias C. Noc  PrimeNet  5  20040825 15:42 
amount of memory needed for Stage 2 (factor)  pin  Software  13  20030318 19:54 