Page 5 of 5 FirstFirst 12345
Results 161 to 194 of 194

Thread: Factor bragging

  1. #161
    Hater of webboards
    Join Date
    Feb 2003
    Location
    KÝbenhavn, Denmark
    Posts
    205
    This one isn't as smooth as the one I found earlier this month, but still pretty smooth:

    4506302931860941 | 19249*2^10139378+1
    4506302931860940 = 2^2*3*5*7*73*199*293*911*2767

  2. #162
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    Secondpass...half way through the range on B1=B2=20000. Will up this depending on the rate of double-check tests.

    1393019896005342 | 24737*2^4351903+1

    (p just over 2^50)

    p-1 = 2 * 3^2 * 11 * 167 * 557 * 5399 * 14009

  3. #163
    I got a big one this morning:

    104061448755062288629 | 10223*2^3927977+1

    BTW, can someone check their logs and tell me how much time a current doublepass PRP takes on a P4. Also let me know the speed of your machine.
    Thanks.

  4. #164
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    Nice.

    n=3870847 took 15 hours on a P4 3.0GHz running Linux
    n=3876754 took 15 hours on a 3.0GHz Xeon running Win2k Server.

  5. #165
    Originally posted by garo
    104061448755062288629 | 10223*2^3927977+1
    p-1 = 2^2 x 3 x 109 x 173 x 643 x 4177 x 6217 x 27541

  6. #166
    Moderator vjs's Avatar
    Join Date
    Apr 2004
    Location
    ARS DC forum
    Posts
    1,331
    Garo,

    What's your success rate using the small bounds. And do you think it's worth the effort to P-1 the unfactored ranges? If so I'll start a new thread for those n 4M<n<5M that are previously untested.

    At the rate we are proceeding with these doublechecks, ~1K tests per day and less than <21K between 4M<n<5M. I have a feeling we will double check out to at least 5M fairly soon, even if the firstpass que is populated.

  7. #167
    On my 2.6GHz the PRP should be taking about 900*3000/2600 = 1038 min or 17hr 18min. I tried P-1 with Pfactor with sieve depth being the correct 49.7. The lowest factor value for which Prime95 worked was 2.7 which gave me bounds of B1=20k and B2=165K. With these bounds the chance of finding a factor was 0.435 and the test took about 620 seconds. Hence P-1 was saving one test every 2375 minutes.

    Hence we can conclude that:

    1) P-1 is not worth it. You can do a test in half the time it takes to find a factor.
    2) Prime95's calculation is accurate and when it says no point doing P-1 factoring, there really is no point doing P-1 factoring.

  8. #168
    Hater of webboards
    Join Date
    Feb 2003
    Location
    KÝbenhavn, Denmark
    Posts
    205
    This one is smoother than your average factor:
    18628509020177411 | 67607*2^10629251+1
    18628509020177410 = 2*5*17*1297*1601*6553*8053

  9. #169
    Moderator vjs's Avatar
    Join Date
    Apr 2004
    Location
    ARS DC forum
    Posts
    1,331
    Not bad HC... not bad at all. The smoothest factor was found by sieve above post.

    But yours certainly ranks in the smoothest I've seen for P-1 thus far.

  10. #170
    Hater of webboards
    Join Date
    Feb 2003
    Location
    KÝbenhavn, Denmark
    Posts
    205
    Originally posted by vjs
    Not bad HC... not bad at all. The smoothest factor was found by sieve above post.

    But yours certainly ranks in the smoothest I've seen for P-1 thus far.
    The smoothest I've found by P-1 is:
    268260631411561 | 10223*2^5240741+1
    268260631411560=2^3*3*5*101*241*293*463*677

    Back in the early days of P-1 mklasson found:
    40315798264717 | 21181*2^4031084+1
    40315798264716=2^2*3^3*13*211*367*601*617

  11. #171
    I love 67607
    Join Date
    Dec 2002
    Location
    Istanbul
    Posts
    752
    Both cool...

  12. #172
    Moderator vjs's Avatar
    Join Date
    Apr 2004
    Location
    ARS DC forum
    Posts
    1,331
    Those are certainly impressive.

  13. #173
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    Hurrah, after weeks of nothing from P-1 I finally get one at 6:47am on New Years Day.

    7233758839303943 | 24737*2^10645207+1

    P-1 = 2 * 11 * 29 * 97 * 271 * 2333 * 184879
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  14. #174
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    1058699706255400291 | 33661*2^10649232+1

    p-1 = 2 * 3 * 5 * 29 * 193 * 7607 * 28549 * 29033
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  15. #175
    Senior Member
    Join Date
    Jan 2003
    Location
    UK
    Posts
    479
    Just found with ECM @ 25 digits

    6112285295043972389 | 67607*2^7691+1

    which was the 4th smallest unfactored n for k=67607

  16. #176
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    I'm doing P-1 on 200000 to 250000 but I just submitted these factors:-

    110339071626803 | 33661*2^224160+1
    4802938257372379 | 55459*2^228718+1
    3068443382948634853 | 21181*2^231548+1

    without logging in. Should be assigned to user 8141. Ta.
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  17. #177
    Senior Member
    Join Date
    Jan 2003
    Location
    UK
    Posts
    479
    ECM found a factor in curve #3, stage #2
    Sigma=5670788764645674, B1=7400, B2=740000.
    10223*2^96221+1 has a factor: 278687290515007924794729914252113

    33 digits. And ECM reports it as being prime. Biggest for us this year.

  18. #178
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    Quote Originally Posted by MikeH
    ECM found a factor in curve #3, stage #2
    Sigma=5670788764645674, B1=7400, B2=740000.
    10223*2^96221+1 has a factor: 278687290515007924794729914252113

    33 digits. And ECM reports it as being prime. Biggest for us this year.
    Good work but I'm afraid it is composite:-

    642379309914469 x 433836031475102077
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  19. #179
    Senior Member
    Join Date
    Jan 2003
    Location
    UK
    Posts
    479
    Quote Originally Posted by Greenbank
    Good work but I'm afraid it is composite:-

    642379309914469 x 433836031475102077
    Ahh. Must check my ECM settings for primality testing.

  20. #180
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    If it's under 2^64 then I use the linux command line program 'factor'.

    If it's bigger than 2^64 then I just stick it through Alpetron's applet: http://www.alpertron.com.ar/ECM.HTM
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  21. #181
    Senior Member
    Join Date
    Jan 2003
    Location
    UK
    Posts
    479
    Thanks for the link. Very useful and interesting.

  22. #182
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    3617343986912807923736443 | 67607*2^202131+1

    p-1 = 2 * 3^2 * 71 * 263 * 9209 * 11383 * 90847 * 1130117

    B1=1M B2=100M
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  23. #183
    you realize that by raising the B1 by 131K yo ucould have found it without performing stage 2

  24. #184
    Quote Originally Posted by Keroberts1
    you realize that by raising the B1 by 131K you could have found it without performing stage 2
    How much time (percentage) would it have saved?

    Which would have been better?
    Raising B1 by 131K, or lowering B1/B2 by a factor of 10?

  25. #185
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    But how would I have known to do that?

    You've got to set bounds without knowing what the factors will look like.
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  26. #186
    I love 67607
    Join Date
    Dec 2002
    Location
    Istanbul
    Posts
    752
    If I'm not mistaken, Prime95 suggests a B2/B1 ratio of around 20 for B1 values at 1,000,000.

  27. #187
    Moderator vjs's Avatar
    Join Date
    Apr 2004
    Location
    ARS DC forum
    Posts
    1,331
    Yup that's always the point...

    One could also say, you could have simply taken the number

    67607*2^202131+1

    and divided it by

    3617343986912807923736443

    Seriously though, what were your memory requirements like for the stage2 portion. Also time to complete for each stage, a 1:100 ratio for B1:B2 seems a little high but it works.

    Are you doing stage two with prime95 have they married the two clients yet.

  28. #188
    Senior Member
    Join Date
    Jun 2005
    Location
    London, UK
    Posts
    271
    It was a windows box that wasn't networked and that I would only visit once a week or so. So I wanted to give it a big chunk of work without worrying about it, hence the large bounds.
    Quad 2.5GHz G5 PowerMac. Mmmmm.
    My Current Sieve Progress: http://www.greenbank.org/cgi-bin/proth.cgi

  29. #189
    Senior Member
    Join Date
    Jan 2003
    Location
    UK
    Posts
    479
    [Fri Feb 24 07:35:05 2006]
    ECM found a factor in curve #80, stage #2
    Sigma=4857056233298550, B1=250000, B2=25000000.
    33661*2^5112+1 has a factor: 1462205790618779672559199619

    28 digits. 6th smallest n for that k. And it realy is prime this time.

  30. #190
    Knight of the Old Code KWSN_Dagger's Avatar
    Join Date
    Feb 2005
    Location
    Western Canada
    Posts
    61
    [Sat May 13 01:18:10 2006]
    P-1 found a factor in stage #2, B1=70000, B2=822500.
    24737*2^11050087+1 has a factor: 594262015630211281

    p-1= 2 ^ 4 x 3 x 5 x 11 x 17093 x 54449 x 241861

    2^4??

    And of course it has to be a composite.

  31. #191
    [Fri Oct 26 22:49:45 2007]
    P-1 found a factor in stage #2, B1=130000, B2=2200000.
    55459*2^15009238+1 has a factor: 5155366181720738537

    and the factor is prime

  32. #192
    [Fri Dec 14 17:07:25 2007]
    ECM found a factor in curve #2260, stage #1
    Sigma=7131277753749641, B1=3000000, B2=300000000.
    10223*2^1181+1 has a factor: 2869295942753555058435842630879466239475749080003

    The factor is prime.

    49 digits long.

  33. #193
    Moderator vjs's Avatar
    Join Date
    Apr 2004
    Location
    ARS DC forum
    Posts
    1,331
    Wow that is actually quite the find!!! Well done.

    Did you check to see if the residual is prime or not? ( nope it's composite) I would say probably not prime but it would be interesting to know.

    P-1 = 2 x 3 ^ 2 x 23 x 189661 x 39 361343 990616 327487 x 928 382719 429012 307749
    P+1 = 2 ^ 2 x 40037 x 106 442681 x 4 343431 551583 x 38752 974121 352341 178651

    Nice....

  34. #194
    11878266738982198597668979 | 10223*2^39449+1
    6650798327357434873224599831 | 10223*2^10757+1
    650124655703350600814106133 | 10223*2^15437+1
    9419400746144284880591 | 10223*2^41285+1
    4380505951119731733855769913 | 10223*2^17477+1
    13217355082313000541253 | 10223*2^42797+1

    Theres a few more factors that my machine found overnight. They've all been verified and submitted.

    On the 49 digit factor I haven't done any tests with the residual other than just testing to see if the factor was prime or not.

Page 5 of 5 FirstFirst 12345

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •