20090709, 14:45  #12 
P90 years forever!
Aug 2002
Yeehaw, FL
67·109 Posts 
Sorry for not bringing this up earlier: PRP iteration timings are about 2.5% faster if you select an exponent that is a multiple of the FFT length.

20090710, 07:29  #13 
Jun 2009
677 Posts 
I think I remember something about sieving being fatser when the binary representation of n contains mostly "0" bits. Are there any numbers which meet both criteria?

20090806, 21:45  #14  
Jan 2005
Caught in a sieve
5×79 Posts 
Now you can thank PG for Sieving and for finding a twin prime!
Quote:


20090807, 13:11  #15 
Account Deleted
"Tim Sorbera"
Aug 2006
San Antonio, TX USA
10253_{8} Posts 
Congrats to all involved for the new twin primes!
What are the primes? 
20090807, 20:02  #16 
Apprentice Crank
Mar 2006
2×227 Posts 

20090807, 20:42  #17 
I quite division it
"Chris"
Feb 2005
England
31×67 Posts 
You could be giving away more than you think.

20090808, 01:06  #18 
Feb 2007
D3_{16} Posts 
Congrats to everyone who participated/helped out with the Twin project. Thanks PG & TP project. The question is Now what?
Now what do we do Mooomooo ? Give us some direction. 
20090808, 01:17  #19 
Apprentice Crank
Mar 2006
111000110_{2} Posts 
I've looked over a previous poll: http://www.mersenneforum.org/showthread.php?t=6974 and some ideas on this thread. Based on that, I've made a preliminary decision to sieve the range 1<k<10M for 480000<n<500000. The chance of finding a twin in that range is slightly over 90%, and any nontwin primes found in that range will make it to the top 5000 list (their rank will be 3600th largest as of today).
Does anyone have any suggestions or comments? If there aren't any major objections, we'll start the sieve early next week. 
20090808, 02:28  #20  
Apprentice Crank
Mar 2006
2·227 Posts 
Quote:
Code:
1000000000:T:0:2:3 18459 480001 59925 480001 94509 480001 9225 480002 36513 480002 14319 480003 16761 480003 67749 480003 98331 480003 but tpfactors only has: 1164933401  94509*2^480001+1 1231256737  18459*2^480001+1 1482274247  59925*2^4800011 None of the n=480002 or n=480003 factors show up (1521564647  9225*2^480002+1, 1243389379  67749*2^4800031, and some others were missing). Does anyone know what happened, and how to fix it? 

20090808, 02:38  #21 
Feb 2007
323_{8} Posts 
Mooomooo i like your idea. I am onboard. Also referring to geoff previous post. We would have to do individual n's using newpgen and then combine them see if that fixes the problem? and then we can continue with tpsieve.
thanks cipher 
20090808, 02:55  #22 
A Sunny Moo
Aug 2007
USA (GMT5)
6249_{10} Posts 
That would essentially mimic the result of what MooMoo just did manually above. AFAIR, you have to either sieve each n separately using tpsieve or NewPGen (for tpsieve you can use a batch file, and for NewPGen you can use the increment counter), or the whole batch together with sr2sieve.
Last fiddled with by mdettweiler on 20090808 at 02:55 
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