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 2005-04-10, 22:11 #1 R.D. Silverman     Nov 2003 746010 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.....
 2005-04-10, 22:27 #2 dave_dm   May 2004 24·5 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
 2005-04-11, 06:33 #3 akruppa     "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
2005-04-11, 11:28   #4
R.D. Silverman

Nov 2003

1D2416 Posts

Quote:
 Originally Posted by akruppa 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
It *is* on Paul's website: on the ecmnet page:

501 62 31069150378873790895208046895771360949463293546412105951449429 2^2034+1 110000000 1507467457 2005-04-10 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!!!!!!

 2005-04-11, 12:37 #5 akruppa     "Nancy" Aug 2002 Alexandria 246710 Posts Ah, it's on the automatically generated new factors list, http://www.loria.fr/~zimmerma/cgi-bin/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 GMP-ECM was useful. Alex
 2005-04-11, 15:20 #6 trilliwig     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. :)
2005-04-14, 12:51   #7
hlaiho

Feb 2005

358 Posts
New factors

Quote:
 Originally Posted by R.D. Silverman I have 5 more days for the linear algebra on 2,1294L. 2,737+ is sieving. CWI has had 12,218+ reserved for ages!!!!!!
I checked today Paul Zimmermann's c120-355 file and I noticed that CWI has
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 2^963-1 were not updated.

Heikki

2005-04-15, 18:11   #8
PBMcL

Jan 2005

2×31 Posts

Quote:
 Originally Posted by hlaiho But factors for numbers 7^254+1 and 2^963-1 were not updated. Heikki
In regards to 2^963-1, I haven't seen the factors posted anywhere. Could someone in the know please post them here or provide a link? Thanks.

Phil McLaughlin

2005-04-15, 18:24   #9
R.D. Silverman

Nov 2003

22·5·373 Posts

Quote:
 Originally Posted by PBMcL In regards to 2^963-1, I haven't seen the factors posted anywhere. Could someone in the know please post them here or provide a link? Thanks. Phil McLaughlin

AFAIK, Bruce Dodson sent them just to Sam Wagstaff Jr.

2005-04-22, 06:25   #10
PBMcL

Jan 2005

768 Posts

Quote:
 Originally Posted by R.D. Silverman AFAIK, Bruce Dodson sent them just to Sam Wagstaff Jr.
The factorization is now up on Paul Zimmerman's c120-355 page:

http://www.loria.fr/~zimmerma/records/c120-355

Phil

 2005-10-04, 09:12 #11 akruppa     "Nancy" Aug 2002 Alexandria 2,467 Posts And yet another p60 by Bruce... seems it's becoming a boring ol' habit for him Code: GMP-ECM 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 (see ftp://ftp.comlab.ox.ac.uk/pub/Documents/techpapers/Richard.Brent/champs.txt) Alex

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