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Old 2016-03-16, 21:26   #3
UberNumberGeek's Avatar
Sep 2008
Masontown, PA

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Originally Posted by VictordeHolland View Post
If you want to attempt to factor these low Mersenne numbers, you'll want to run ECM curves with high bounds. ECM with B1=800,000,000 for starters. Prime95 has options to do that. You could also give GMP-ECM a try for the stage 2. Curves wirh higher bounds can find larger factors, but take longer to complete.
Thank you for replying, Victor!

I am running ECM curves at B1=800,000,000 and B2=80,000,000,000, but on my PC 1 curve takes 2 hours to run, and according to the ECM chart, there are still over 300,000 curves to be run for these numbers at those bounds.

I was hoping that P-1 factoring would find a nice, "smooth" factor and save time. In the 4 months it took my P-1 factoring to complete, I could have only completed a few thousand curves of ECM, still a small percentage.

And, again, I was hoping that, since I have already spent 4 months on P-1 factoring, that I could up the bounds and pick up where I left off and maybe find a decent-sized factor that was bigger than the 65-digit "limit" those bounds imply.

Thank you again!
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