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Old 2007-11-09, 02:30   #34
Kosmaj
 
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Posts about k*10^n-1 moved to another thread.

Please post new messages on this topic there.
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Old 2007-12-14, 21:18   #35
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Default New Conjectures 'R Us prime search effort

Hi all...

Come check out the new "Conjectures 'R Us" prime search effort here. There's plenty of bases and k's for everyone to search and have fun.


Gary
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Old 2007-12-26, 19:13   #36
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Check this out... if this is part of primegrid, then we will fall to #5 I guess... (in terms of score)

Last fiddled with by Cruelty on 2007-12-26 at 19:14
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Old 2007-12-26, 19:21   #37
mdettweiler
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Quote:
Originally Posted by Cruelty View Post
Check this out... if this is part of primegrid, then we will fall to #5 I guess... (in terms of score)
I don't see PrimeGrid in the prover code...though I can't imagine why someone would be searching for Woodall primes outside of PrimeGrid (since they would be duplicating a lot of work, especially the sieving work). It's roughly in the range that PrimeGrid is searching, though, so I wouldn't be surprised if it was a PrimeGrid thing, just that the finder forgot to include PrimeGrid in his prover code. (I'm sure if that's the case, though, the Prime Pages people will fix it.)
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Old 2007-12-26, 21:46   #38
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Cruelty

We can sustain this one, still 4th, but not the next larger one.
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Old 2007-12-27, 00:29   #39
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Quote:
Originally Posted by Kosmaj View Post
We can sustain this one, still 4th, but not the next larger one.
That is why we are all waiting for your k=7 prime + some other megabit primes are long overdue from me
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Old 2008-01-17, 00:31   #40
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Congrats to Richard (L185) on a huge prime
3139*2^3321905-1

only 3 digits shy of one million digits! He found the 9th SoB prime in 2005 (4847*2^3321063+1, 999744 digits) and is currently ranked 14th person by score.

Last fiddled with by Kosmaj on 2008-01-17 at 00:31
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Old 2008-02-02, 15:09   #41
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Prof. Cooper found another very large prime:
7 * 2^3015762+1 (907836 digits).

By the way, can I somewhere find an overview how fast the different forms of numbers can be tested at the moment (for a example a comparison of the forms k*2^n-1, k*2^n+1, k*b^n+/-1)?

Last fiddled with by Retep on 2008-02-02 at 15:10
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Old 2008-02-03, 14:03   #42
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Yes, that's his largest prime after two Mersennes.
We are now waiting to see is it a Fermat or a GF divisor, I'm sure he is now working on those tests.

As for the processing speed, when b=2, both -1 and +1 are about the same for the given k. When b>2 it's much slower (except, of course when b is a power of 2).
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Old 2008-03-08, 23:32   #43
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4*3^311835-1 (148784 digits)
Attached is a list of primes for k=4 b=3.
Attached Files
File Type: txt PRIMES_k=4_b=3.txt (458 Bytes, 156 views)
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Old 2008-03-10, 04:55   #44
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Cruelty

Congrats on a nice effort and a nice prime!

I remember that prof. Iskra had a special speed-up for
a^2*3^n+1, (n odd)

and found a number of large primes. I just found that his article is now available free of charge! The Corollary 2.3 won't be difficult to implement uisng GMP...
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