Factoring humongous Cunningham numbers - Page 97

bsquared · 2013-02-08, 03:54

Cool, I love threebies.

RichD · 2013-02-08, 04:21

Has anyone ever hit a quad? Meaning 2/9 SNFS is 22.2% making a really tiny probability of hitting a four-banger.

LaurV · 2013-02-08, 05:01

With the usual ECM to 30% which people use (I use 33% for the range of C120 I try to factor, in yafu I have "plan=custom" and "pretest_ratio=0.33") the chances to hit a 4-split are quite a zero divided by three... :D

[edit: wow! hitting 3 "top page" in 3 posts, I swear I did not do this intentionally! I am not so good at mental calculus to see in a blink that 1058 is 0 (mod 23), neither so crazy to do this by calculator for all threads I visit, moreover, one of the other two was caused by a crosspost! Today is a good day!

]

rcv · 2013-02-08, 06:22

Quote:

Originally Posted by RichD

Has anyone ever hit a quad?

It looks like they did back in 1997. c168 = p36 * p37 * p41 * p56
See lines 4076 through 4078 of Wagstaff's Page 77

xilman · 2013-03-03, 19:17

Here are the 14 factors reported to me since the last update on 2013-01-18.

Code:

9+8	221	C171	545740033998333814293765310812962471999109426064229211179.	P114						B Buhrow		SNFS	2013-01-21
11+2	208	C181	4007810002658706879891663921557250185460592506816881042387976285153675507235873.	P103			B Buhrow		SNFS	2013-01-21
7-4	287	C203	16296685989918205666691222572158121303705213228915799437390338892911386177981.	P127				B Buhrow		SNFS	2013-01-31
4+3	409	C147	164613620069941029703766535542533742867179043381833069.	P94							R Smith			GNFS	2013-02-01
7+6	262	C201	650684982665929473914310356586078821560254858817.	C153							R Silverman		ECM	2013-02-04
7-3	299	C217	1497780723898541954402942574017064792681335586911942854818307.	C157						T Womack		SNFS	2013-02-07
7-3	299	C157	1553427137055387523990325068980165910660575660216019565381853262915933.	P88					T Womack		SNFS	2013-02-07
5-2	325	C156	74127027645704797340405175339425680824404648589408837172949526290401.	P89					J Becker		SNFS	2013-02-13
12-11	215	C160	7133142421482294140070409869869064331444461701070750838140729217271.	P93					J Becker		SNFS	2013-02-15
10+7	209	C178	21597775413601991163593249792779723279003188360702250382441.	C120						J Becker		SNFS	2013-02-16
10+7	209	C120	128729544307376640692876728564343754486974120104540163897921.	P61						J Becker		SNFS	2013-02-16
10+7	202	C147	2519772133278089486434479544442547317630435253390568209582573636269.	P81					R Smith			GNFS	2013-02-19
10+7	208	C170	4118878150088907283771974063815075952684878169161919124304161.	P109						J Becker		SNFS	2013-02-27
7+3	275	C156	79542985457377068577021458651092204981075603109297504158277814776626484751.	P82				J Becker		SNFS	2013-02-28

There are now 475 composite cofactors left in the tables. The ECMNET server has been updated in tandem with the web pages.

It's nice to see that ECM is still finding factors.

Paul

R.D. Silverman · 2013-03-04, 13:06

Quote:

Originally Posted by xilman

Here are the 14 factors reported to me since the last update on 2013-01-18.

Code:

9+8	221	C171	545740033998333814293765310812962471999109426064229211179.	P114						B Buhrow		SNFS	2013-01-21
11+2	208	C181	4007810002658706879891663921557250185460592506816881042387976285153675507235873.	P103			B Buhrow		SNFS	2013-01-21
7-4	287	C203	16296685989918205666691222572158121303705213228915799437390338892911386177981.	P127				B Buhrow		SNFS	2013-01-31
4+3	409	C147	164613620069941029703766535542533742867179043381833069.	P94							R Smith			GNFS	2013-02-01
7+6	262	C201	650684982665929473914310356586078821560254858817.	C153							R Silverman		ECM	2013-02-04
7-3	299	C217	1497780723898541954402942574017064792681335586911942854818307.	C157						T Womack		SNFS	2013-02-07
7-3	299	C157	1553427137055387523990325068980165910660575660216019565381853262915933.	P88					T Womack		SNFS	2013-02-07
5-2	325	C156	74127027645704797340405175339425680824404648589408837172949526290401.	P89					J Becker		SNFS	2013-02-13
12-11	215	C160	7133142421482294140070409869869064331444461701070750838140729217271.	P93					J Becker		SNFS	2013-02-15
10+7	209	C178	21597775413601991163593249792779723279003188360702250382441.	C120						J Becker		SNFS	2013-02-16
10+7	209	C120	128729544307376640692876728564343754486974120104540163897921.	P61						J Becker		SNFS	2013-02-16
10+7	202	C147	2519772133278089486434479544442547317630435253390568209582573636269.	P81					R Smith			GNFS	2013-02-19
10+7	208	C170	4118878150088907283771974063815075952684878169161919124304161.	P109						J Becker		SNFS	2013-02-27
7+3	275	C156	79542985457377068577021458651092204981075603109297504158277814776626484751.	P82				J Becker		SNFS	2013-02-28

There are now 475 composite cofactors left in the tables. The ECMNET server has been updated in tandem with the web pages.

It's nice to see that ECM is still finding factors.

Paul

I just found another. It's been a while. It was a p51 with a composite
cofactor.

xilman · 2013-03-04, 15:27

Quote:

Originally Posted by R.D. Silverman

I just found another. It's been a while. It was a p51 with a composite cofactor.

Yes, thanks. It arrived in my mbox a little while ago.

Paul

jyb · 2013-03-04, 16:25

Quote:

Originally Posted by R.D. Silverman

I just found another. It's been a while. It was a p51 with a composite
cofactor.

Bob, can you give us all an idea of how many curves you've been running, and at what B1? It would be nice to keep Paul's ECMnet server up to date with that so it's not handing out useless work.

Thanks.

jyb · 2013-03-04, 16:35

Quote:

Originally Posted by xilman

There are now 475 composite cofactors left in the tables. The ECMNET server has been updated in tandem with the web pages.

It's nice to see that ECM is still finding factors.

Paul

Two numbers have gone missing. They no longer appear on Tom's reservation page, so I assume they have been factored, but apparently Paul hasn't received word of them. The two are 7-5,265 and 9+5,247. The first of these does appear to have been updated in factordb.com, on February 11. Does anybody know anything about the other one?

xilman · 2013-03-04, 17:15

Quote:

Originally Posted by jyb

Bob, can you give us all an idea of how many curves you've been running, and at what B1? It would be nice to keep Paul's ECMnet server up to date with that so it's not handing out useless work.

Thanks.

I'd been meaning to make that request myself but hadn't got a round tuit, so thanks.

It would be nice to record the work in the server but your choice of "useless" is a little emphatic IMO. Slightly sub-optimal may be more appropriate. Unless Bob has (a) vastly more resources than I suspect and [(b) hasn't been reporting all his findings or (c) has been amazingly unlucky], his efforts are unlikely to persuade the server from handing out tasks with B1=43M for some substantial time yet.

Paul

R.D. Silverman · 2013-03-04, 17:18

Quote:

Originally Posted by jyb

Bob, can you give us all an idea of how many curves you've been running, and at what B1? It would be nice to keep Paul's ECMnet server up to date with that so it's not handing out useless work.

Thanks.

Sure.

I've been running each number for one day with my limited number of machines.

This typically means about 800 curves with B1 = 200M. The exact number
of curves varies from day to day owing to machine availability.

2013-02-08, 05:01	#1059
LaurV Romulan Interpreter Jun 2011 Thailand 3·3,221 Posts	With the usual ECM to 30% which people use (I use 33% for the range of C120 I try to factor, in yafu I have "plan=custom" and "pretest_ratio=0.33") the chances to hit a 4-split are quite a zero divided by three... :D [edit: wow! hitting 3 "top page" in 3 posts, I swear I did not do this intentionally! I am not so good at mental calculus to see in a blink that 1058 is 0 (mod 23), neither so crazy to do this by calculator for all threads I visit, moreover, one of the other two was caused by a crosspost! Today is a good day! ] Last fiddled with by LaurV on 2013-02-08 at 05:19

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2013-02-08, 03:54	#1057
bsquared "Ben" Feb 2007 7·503 Posts	Cool, I love threebies.

2013-02-08, 04:21	#1058
RichD Sep 2008 Kansas 2·3·5·113 Posts	Has anyone ever hit a quad? Meaning 2/9 SNFS is 22.2% making a really tiny probability of hitting a four-banger.