mersenneforum.org Factoring humongous Cunningham numbers
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 2006-04-11, 01:12 #12 jasong     "Jason Goatcher" Mar 2005 5·701 Posts Mr. Silverman, if you're willing to accept the fact that I have zero knowledge of how ecm works, and you don't care that I don't care, I would be happy to give you a week or two of time on my lowly 1.75GHz Sempron. Just post some ecm parameters and I can get on it right away. Edit: I apologize, I didn't see post #6. I'm going to attempt to get it running sometime tonight. Edit2: Could someone post some stuff about filenames and how to use post #6 info. Sorry for my ignorance. Last fiddled with by jasong on 2006-04-11 at 01:22
 2006-04-11, 01:39 #13 jasong     "Jason Goatcher" Mar 2005 5×701 Posts Mr. Silverman, could you please post more info about your curves? I learned the hard way that different B1, B2 values mean that a different number of curves is necessary. Can I assume that your B1=1e6 means B2=8.4e8? (I printed out part of a web page a while back, not realizing B1/B2 parameters weren't set in stone. In the instance of these parameters it says 35-digits and 1100 curves. Is this correct? Or is B2=B1*100? Or are they both wrong?)
 2006-04-11, 02:03 #14 rogue     "Mark" Apr 2003 Between here and the 127568 Posts 14273530385368339 is a factor of 389-. The cofactor is composite.
2006-04-11, 10:41   #15
R.D. Silverman

Nov 2003

163158 Posts

Quote:
 Originally Posted by John Renze The C87 cofactor of 3^636-2^363 factors thusly: 51367404262568392429656240517252067923 x 7705482404964763837578788370404060262063595624219 This factorization was found using Msieve v. 1.01.
Much obliged.

Bob

2006-04-11, 10:43   #16
R.D. Silverman

Nov 2003

73·101 Posts

Quote:
 Originally Posted by jasong Mr. Silverman, could you please post more info about your curves? I learned the hard way that different B1, B2 values mean that a different number of curves is necessary. Can I assume that your B1=1e6 means B2=8.4e8? (I printed out part of a web page a while back, not realizing B1/B2 parameters weren't set in stone. In the instance of these parameters it says 35-digits and 1100 curves. Is this correct? Or is B2=B1*100? Or are they both wrong?)
It is not important. I ran several hundred curves with B1 = 1M.
This should have cleared out factors to 30 digits. Run whatever curves you like.

2006-04-11, 10:56   #17
R.D. Silverman

Nov 2003

73×101 Posts

Quote:
 Originally Posted by John Renze The factors of the C88 are: 1315651155909947565347700897218133001 1338208112877762546551051364373633349610010436196551
Thanks.

If anyone would like to see the entire set of tables (a^n +/- b^n)
for (a,b) = 1, a <=12, b < a, I will post them, but be warned:
the file is ~600Kb.

I do not work on them a lot.

Note that these tables are the "homogeneous" analogue of the Cunningham
tables.

2006-04-11, 11:15   #18
R.D. Silverman

Nov 2003

73·101 Posts

Quote:
 Originally Posted by Wacky [SOAPBOX] John, I would like to thank you for completing this factorization. Sometimes those of us who are committing our resources to more "cutting edge" problems
Actually, I don't do "cutting edge" anymore. I don't have the CPU
resources. I just clean up the "moderate sized" pieces that trail just

I wish I did have the resources... I'd love to go after M1061..........
However, even if I had the sieving resources, solving the matrix for
this number will be a real problem...

Hey! perhaps we could get cajole IBM into lending "Big Blue" to do the
matrix once we get around to organizing the sieving????

I know Don Coppersmith. Perhaps I might ask him.

Bob

2006-04-11, 12:10   #19
xilman
Bamboozled!

May 2003
Down not across

100110011000012 Posts

Quote:
 Originally Posted by R.D. Silverman Thanks. If anyone would like to see the entire set of tables (a^n +/- b^n) for (a,b) = 1, a <=12, b < a, I will post them, but be warned: the file is ~600Kb. I do not work on them a lot. Note that these tables are the "homogeneous" analogue of the Cunningham tables.
I suggest that rather than post the tables, you post a URL to a site that holds them.

If you don't have them hosted anywhere, I'll volunteer to put them on my site if you wish.

Paul

2006-04-11, 12:11   #20
R.D. Silverman

Nov 2003

73·101 Posts

Quote:
 Originally Posted by xilman I suggest that rather than post the tables, you post a URL to a site that holds them. If you don't have them hosted anywhere, I'll volunteer to put them on my site if you wish. Paul

We are behind a strict firewall. I will send them to you.

 2006-04-11, 15:27 #21 smh     "Sander" Oct 2002 52.345322,5.52471 29·41 Posts Can somenody explain me how to create a SNFS polynomial for these numbers?
2006-04-11, 16:37   #22
xilman
Bamboozled!

May 2003
Down not across

3×52×131 Posts

Quote:
 Originally Posted by R.D. Silverman We are behind a strict firewall. I will send them to you.
Got them, thanks.

It will take me a little time to put them on the web as I need to convert your mail to separate files and then to write an HTML wrapper. I'll probably put a separate copy of the tables in my standard format too --- one designed to be easily parsed by people and by programs.

When the page is ready I'll post the URL here.

Paul

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