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Thread: Factor bragging

  1. #161
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    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
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    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
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    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
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    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
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    This one is smoother than your average factor:
    18628509020177411 | 67607*2^10629251+1
    18628509020177410 = 2*5*17*1297*1601*6553*8053

  9. #169
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    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
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    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
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    Both cool...

  12. #172
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    Those are certainly impressive.

  13. #173
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    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
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    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
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    Just found with ECM @ 25 digits

    6112285295043972389 | 67607*2^7691+1

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

  16. #176
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    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.
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  17. #177
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    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
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    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
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  19. #179
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    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
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    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.
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  21. #181
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    Thanks for the link. Very useful and interesting.

  22. #182
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    3617343986912807923736443 | 67607*2^202131+1

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

    B1=1M B2=100M
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  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
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    But how would I have known to do that?

    You've got to set bounds without knowing what the factors will look like.
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  26. #186
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    If I'm not mistaken, Prime95 suggests a B2/B1 ratio of around 20 for B1 values at 1,000,000.

  27. #187
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    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
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    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
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    [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
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    [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
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    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.

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