20080201, 21:51  #1 
"Lucan"
Dec 2006
England
2·3·13·83 Posts 
exponents 42M43M
The numbers of exponents just listed as available
seem abnormally large  as if they had not removed the ones which have been factored. 
20080202, 01:51  #2 
Einyen
Dec 2003
Denmark
3,037 Posts 
56,915 primes between 42M and 43M. According to ftp://mersenne.org/gimps/factors.zip there are 34,650 known factors between 42M43M (haven't checked if there are several factors for same exponent), so that leaves 22,265 unknowns.

20080202, 10:22  #3  
"Lucan"
Dec 2006
England
2×3×13×83 Posts 
Quote:


20080202, 14:25  #4 
Einyen
Dec 2003
Denmark
3,037 Posts 
Its not that far off then, its probably 1522 exponents in factors.zip which has more than 1 factor listed.

20080202, 19:24  #5 
"Lucan"
Dec 2006
England
2·3·13·83 Posts 
Here are the percentages of Mersennes factored by range:
015M: 63.54% 15M17.5M: 62.59% 17.5M20M: 62.87% 20M25M: 63.04% 25M30M: 62.67% 30M35M: 62.64% 35M40M: 62.41% It is hardly overextrapolating to guess that from 40M80M the percentage factored before LL testing takes place will be close to 62.5% (5/8). The corresponding % we have got for 42M43M is 58.2% which is significantly lower than expected. 
20080202, 20:45  #6 
"Lucan"
Dec 2006
England
2·3·13·83 Posts 

20080202, 22:08  #7 
Sep 2006
Brussels, Belgium
2^{2}·7·59 Posts 
Do not forget that earlier versions of the program Prime95 factored one bit higher... For the current range of exponents that would be up to 69 bits compared to 68 bits with version 24 of Prime95. That removes 1.5% of the difference.
Jacob 
20080202, 23:15  #8  
"Lucan"
Dec 2006
England
194A_{16} Posts 
Quote:
a factor between 2^68 and 2^69 is ~1/68 ~1.5%. But this accounts for 1.5% of the 40% of exponents which have no factor below 2^68, i.e. 0.6% of all the prime exponents. The discrepancy is bigger than this. David 

20080202, 23:37  #9  
"Mark"
Feb 2003
Sydney
3·191 Posts 
Quote:
It could be (& I really hope so!) that the excess exponents are not actually available for assigning, like the way TF assignments go back into the "available" column when they're completed, because the v4 primenet server couldn't handle the change to factoring cutoffs in prime95 v24.12 very well. Roll on PrimeNet version 5! 

20080217, 11:11  #10 
"Lucan"
Dec 2006
England
194A_{16} Posts 
Now that some of these have been allocated for LLtesting ,
can we now identify some of the 1500 which have already been factored? 
20080226, 15:38  #11 
"Lucan"
Dec 2006
England
2·3·13·83 Posts 
70 in the "factored" column for 42.0M42.1M.
Is this not further evidence that our suspicions are well founded? 
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