20170109, 21:06  #1 
Dec 2011
After milion nines:)
2^{2}×337 Posts 
Algebraic factors in sieve files
I was little bored so using Batalov script I found many algebraic factors that can be remove before starting LLR
LIST k8 s86 k248832 s145 k8 s182 S205 k4 s230 k27 s252 k64 s259 k27 s328 k4 s335 k4 s875 k8 s911 k8 s930 k8 s953 k8 s993 I targeted "big ones" but also look at few "small" ranges All factors are in zip file attached to this thread And as you can see this time all factors are from S bases. I hope Batalov is not angry that I used his script Last fiddled with by pepi37 on 20170109 at 21:08 Reason: Add more text 
20170110, 18:40  #2 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
2^{3}·7·163 Posts 
It would be interesting if it was not mentioned quite a few times already.
What is indeed interesting is that every time this is mentioned CRUS answers: "there is no problem! srsieve removes these, you just don't know it!" Well, either it doesn't or the hosted sieved files were done incorrectly. Checking sievesierpbase252500K1M.txt ... yep, the n%3==0 are still there (243 of them). Checking sievesierpbase328900K1M.txt ... yeah. The same. Checking sievesierpbase875600K1M.txt ... 1025 useless candidates are still there. ...and so on. P.S. Why would I "be angry" at the clear signs that someone is steadily learning something. It is almost always a good thing. 
20170110, 18:58  #3 
"Mark"
Apr 2003
Between here and the
5,953 Posts 
Serge, I'm sure there are algebraic factors the srsieve is not finding. They come in many forms and the program is only searching for one form. If you have some code idea to implement into srsieve, please share with me.

20170110, 19:42  #4 
"Nuri, the dragon :P"
Jul 2016
Good old Germany
2×7×53 Posts 
I have a suggestion.
Maybe add the option to delete these factors by using Batalov´s script after sieving is done. It´s one more sieving step, but it´s worth it. Code:
Sieving>Search for Algebraic factors>Delete all factors using srfile 
20170110, 20:27  #5  
Dec 2011
After milion nines:)
2^{2}·337 Posts 
Quote:
If you remember, when I ask you to do two of my sequence, I prepare data for you, and remove it before I send it to you :) And it is not irrelevant when you remove it: just remove it before send here :) 

20170110, 20:29  #6 
Dec 2011
After milion nines:)
544_{16} Posts 

20170111, 05:50  #7 
May 2007
Kansas; USA
3×7×487 Posts 
It's possible that some of the sieve files were posted to the pages before more recent versions of srsieve.

20170111, 06:24  #8 
Dec 2011
After milion nines:)
2504_{8} Posts 
[QUOTE=gd_barnes;450791]It's possible that some of the sieve files were posted to the pages before more recent versions of srsieve.[/QUOTE
Even latest srsieve doesnot remove algebraic factors. Remove just small part but doesnot remove all. 
20170111, 10:08  #9 
Dec 2011
After milion nines:)
2^{2}·337 Posts 
It is easy to test: using all latest version of srxsieve if you make 4*20^n+1 from n=1 to 1 M you will get 57250, and after using Batalov script it finds 5087 algebraic factors in that sieve file. So srsieve doesnot remove them, and also sr1sieve or sr2sieve dont remove them

20170111, 13:23  #10 
"Mark"
Apr 2003
Between here and the
5,953 Posts 
As I stated before algebraic factors come in many forms. srsieve only removes one of those forms. If someone can provide to me the other forms then I can modify srsieve to eliminate them.

20170111, 19:10  #11 
"Nuri, the dragon :P"
Jul 2016
Good old Germany
2·7·53 Posts 
Is someone able to post the script in this thread. I searched in the forums for it, but I didn´t found it. :/
I´ve some spare time atm. EDIT: Lucky me. http://www.mersenneforum.org/showpos...&postcount=105 EDIT2: Not so lucky me, seems to be somethink different... Last fiddled with by MisterBitcoin on 20170111 at 20:01 
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