20050410, 22:11  #1 
"Bob Silverman"
Nov 2003
North of Boston
2^{2}·1,877 Posts 
And the hits just keep on coming.....
Bruce Dodson has just found ANOTHER 60+ digit factor with ECM.....
It is getting tough to keep up with him..... 
20050410, 22:27  #2 
May 2004
120_{8} Posts 
Given how smooth his last factor's group order was, nothing short of
2^2 * 3 * 5 * 7 * 11 * ... * 163 * 167 * 173 would surprise me now Dave 
20050411, 06:33  #3 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
How the heck does he do that? I wouldn't be surprised if he announced a 70 digit factor next week...
Bob, I haven't seen the announcement and PaulZ' page doesn't show the factor yet. Can you tell us what the input number, factor and sigma was? Thanks, Alex 
20050411, 11:28  #4  
"Bob Silverman"
Nov 2003
North of Boston
1D54_{16} Posts 
Quote:
501 62 31069150378873790895208046895771360949463293546412105951449429 2^2034+1 110000000 1507467457 20050410 Bruce Dodson I have 5 more days for the linear algebra on 2,1294L. 2,737+ is sieving. CWI has had 12,218+ reserved for ages!!!!!! 

20050411, 12:37  #5 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
Ah, it's on the automatically generated new factors list, http://www.loria.fr/~zimmerma/cgibin/last.cgi?size, not on the ECMNET Records page.
Magma returns the group order as <2, 6>, <3, 1>, <5, 1>, <7, 1>, <743, 1>, <6143, 1>, <66041, 1>, <698311, 1>, <2253259, 1>, <21053117, 1>, <28982407, 1>, <40945981, 1>, <390171012887, 1> so this time around the large B2 of GMPECM was useful. Alex 
20050411, 15:20  #6 
Oct 2004
tropical Massachusetts
3×23 Posts 
Wow, congratulations to B. Dodson and the developers of GMP/ECM, and maybe Bruce should think about investing in lottery tickets now. :)

20050414, 12:51  #7  
Feb 2005
29 Posts 
New factors
Quote:
finally factored 12^218+1, c191 and it has a factor 1387293413889182892369611621737490690000635951250375091953099809. I also noticed that a number, 11^208+1 c185, reserved for NFSNET, has also factored and it has a factor 937106993318605353391918345676692606835799914934541577963079807089450560607964644697022433. But factors for numbers 7^254+1 and 2^9631 were not updated. Heikki 

20050415, 18:11  #8  
Jan 2005
2·31 Posts 
Quote:
Phil McLaughlin 

20050415, 18:24  #9  
"Bob Silverman"
Nov 2003
North of Boston
2^{2}·1,877 Posts 
Quote:
AFAIK, Bruce Dodson sent them just to Sam Wagstaff Jr. 

20050422, 06:25  #10  
Jan 2005
2·31 Posts 
Quote:
http://www.loria.fr/~zimmerma/records/c120355 Phil 

20051004, 09:12  #11 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
And yet another p60 by Bruce... seems it's becoming a boring ol' habit for him
Code:
GMPECM 6.0 [powered by GMP 4.1.90] [ECM] Input number is 103075013632530613238830214574461224255502947988793595243480832015485960389418448 8555363670791919267623015414248683651966794189351136814962050280634101519243289849021116361370695 4182234370938353277735195926944595191602578792749487517655250803 (242 digits) Using B1=110000000, B2=680270182898, polynomial Dickson(30), sigma=2504147897 Step 1 took 1353464ms Step 2 took 732450ms ********** Factor found in step 2: 186347963875290244607785015115115186185151460498163342326993 Found probable prime factor of 60 digits: 186347963875290244607785015115115186185151460498163342326993 Composite cofactor 553131955343024644418848603267321684781931442658925553104283719219555332273942 8421102459905181068534021574321081080210034361552788286521060856404833277839150016082619531065742 1095171 has 182 digits Report your potential champion to Richard Brent <rpb@comlab.ox.ac.uk> (see ftp://ftp.comlab.ox.ac.uk/pub/Documents/techpapers/Richard.Brent/champs.txt) 
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