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 2004-01-19, 01:39 #34 Xyzzy     Aug 2002 100001011010002 Posts 250M - 500M to 2^32 Just for fun, I'm burning through this range, split between two boxes... It is going *very* fast...
 2004-01-19, 20:42 #35 cheesehead     "Richard B. Woods" Aug 2002 Wisconsin USA 22·3·641 Posts Re: 250M - 500M to 2^32 Of course it's going very fast -- there are only a very small number of candidate factors below 2^32 for each exponent in that range, almost all of which will be eliminated by the small-prime sieve before any need for division into the Mnumber. 2^32 = 4,294,967,296. For p = ~250M, 2p = ~500M. The only 2kp+1 candidate factors below 2^32 are for k = 1,2,3,4,5,6,7,8 and it's unlikely that even one of those will survive the small-prime sieve (e.g., at least two of them must be divisible by 3, at least one by 5, and at least one by 7). For p = ~500M, 2p = ~1G. The only candidate factors below 2^32 are for k = 1,2,3,4, and the chance that any of them will actually need to be divided into the Mnumber is quite small. Let us know how many factors you find, and what percentage that is of the total.
 2004-01-20, 02:26 #36 Xyzzy     Aug 2002 23×1,069 Posts One box has done from 250M to 290M and has found 175,190 factors so far...
2004-01-20, 02:40   #37
nfortino

Nov 2003

3·5·11 Posts

Quote:
 Originally posted by Xyzzy One box has done from 250M to 290M and has found 175,190 factors so far...
That is an impressive 8.5% of the exponents in that range. (Found using http://primes.utm.edu/nthprime/index.php).

 2004-01-21, 11:04 #38 bayanne     "Tony Gott" Aug 2002 Yell, Shetland, UK 24×23 Posts Completed and took about 12 days to do on P166. 140199 factors found from 292104 exponents.
 2004-01-29, 18:38 #39 michael   Dec 2003 Belgium 10000012 Posts Anyone bothered if i explore this region a little deeper? Say i take the exponents that didn't have a factor up to 50 bits depth and search to 55 orso... -michael
2004-01-29, 19:41   #40
bayanne

"Tony Gott"
Aug 2002
Yell, Shetland, UK

24·23 Posts

Quote:
 Originally Posted by michael Anyone bothered if i explore this region a little deeper? Say i take the exponents that didn't have a factor up to 50 bits depth and search to 55 orso... -michael
How are you going to remove the factors found, and set the parameters for this next search?

I'm interested as would like to do the same on the range I worked through....

 2004-01-29, 22:17 #41 michael   Dec 2003 Belgium 5×13 Posts I just use the grep utility Xyzzy talked about in the other thread. Then i edited the text a bit and made the lines in worktodo.ini look like AdvancedFactor=exponent,exponent,50,56 When i tried Factor=exponent it wouldn't work, perhaps cause the exponent is too big for that command, i wouldn't know. I already did 185 to 186M and found 2450 new factors (50-56bit depth) -michael
 2004-01-29, 23:00 #42 hbock     Feb 2003 16310 Posts If you just want to remove exponents, ie. to find a first factor, then that's ok. But if you would like to find more (new) factors then it's better to check all (prime) exponents in the higher bit range or even better : start at 33 bit ! In the latter case you will find lots of already known factors (from the first run 28-50) but also a lot of new factors for exponents where the first factor found was pretty small, ie. <=32 bit.
 2004-02-05, 18:10 #43 ThomRuley     May 2003 29110 Posts 240-250M to 2^50 I was about to build a new computer, so I can take this range. ThomRuley
 2004-02-23, 21:56 #44 ThomRuley     May 2003 29110 Posts Here's an update. I just finished building this computer, and I have already assigned the range 240-250M to my old machine.

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