20070115, 10:04  #1 
Oct 2005
Italy
523_{8} Posts 
Next Exponent(s)
I offer myself to sieve another exponent (maybe the one following n=333,333 ?) and release periodically the presieved files (like Gribozavr did for n=195,000).
I'll use www.twinprimesearch.org to upload the presieved files. I'd like to work alone on this exponent to avoid to transfer big files. Is it possible ? Moreover everybody should go to PrimeGrid to do LLR testing. Last fiddled with by pacionet on 20070115 at 11:00 
20070218, 12:41  #2 
Quasi Admin Thing
May 2005
3×307 Posts 
Moomooo and pacionet, just for curiosity, what is the sieving depth, and how many of the 208 G candidates, is left? At the moment, I've just calculated, that there is 348 years of P4 2.553 GHz of computation left on n=333,333, but of course it will be lover since sieving is still going strong, and since we shouldn't expect to go all the 100 G through before a twin is found... again it is only out of curiosity, and I'm not going to offer any sieving help, since I'm busy trying to find primes with LLR at primegrid, since my computer is now again healthy though it has had its ram reduced to the half
Regards! KEP Ps. I lost track of the thread currently about sieving n=500,000 that's why I asked here in this thread :) 
20070218, 14:26  #3 
Oct 2005
Italy
3×113 Posts 

20080426, 17:42  #4 
Dec 2006
3·11 Posts 
So what's next? Is it Primegrid's 666,666 exponent that is sieved for SG and TP chance or are you palnning a twin only search again, like 500,000 as the exponent. Wouldn't be that efficient. Is there sieving done yet?

20080426, 19:19  #5  
Apprentice Crank
Mar 2006
2·227 Posts 
Quote:
1.) Test n=500,000 as planned earlier. I think cipher's sieving 150G, you'll have to ask him how the progress is on that range. 2.) Change course and follow Gary, Robert, et al's advice on this thread: http://www.mersenneforum.org/showthr...?t=8479&page=2 They're suggesting to sieve a broad k and n range. Sieving will be less efficient, but the LLR tests should not take as long. In that case, the nrange will be from n=450,001 to n=524,288, and the k range will be from k=3 to k=2.8M. I haven't made any final decisions as to which choice to take. The default is option 1, but I'm open to suggestions. 

20080427, 10:42  #6 
Jun 2003
Oxford, UK
753_{16} Posts 
The purpose of option 2 is to virtually guarantee a twin, whereas with picking a single n this is not possible. I would be interested to see how many computer years such an exercise would take, because, testing the option 2 approach at n=71000 will take quite a bit of time so at n=500000 the time must be astronomical. The current record was achieved through good fortune if we look at the statistics.

20080503, 03:52  #7 
May 2007
Kansas; USA
10171_{10} Posts 
Another option might be to 'scale down' a little. I would suggest a "variablen" approach using the range of n=250K350K, of course skipping n=333333. There would be little or no top5000 primes but I think the point here is to find a record twin, not find multitudes of single primes that will quickly drop off the top5000 list. But only you guys know if finding top5000 primes adds significant resources to the project.
By my estimate, PrimeGrid will not find an n=666666 twin or SG for 5+ years, even with a huge amount of resources. I think you want to virtually guarantee that you'll find the largest twin when you do find one. If you choose n=500K or n=450K524288, it's very possible that might take longer than n=666666 for PrimeGrid depending on how many more resources they have than you. Just my two cents... Last fiddled with by gd_barnes on 20080503 at 03:56 
20080503, 12:27  #8 
Jun 2003
Oxford, UK
3·5^{4} Posts 
Amphoria got a positive result for the final test using the many n, low k method:
1294767*2^67708+/1 So this completes all testing of the method... I am now confident it will produce the goods at any level of n. Given the resources available, which are limited, then I suggest an approach similar to Gary, with a goal of finding the largest twin to date in, say, 3 months. It is no use setting a five year goal...people will just not stick with it 
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