mersenneforum.org News
 Register FAQ Search Today's Posts Mark Forums Read

 2010-07-22, 02:11 #12 kar_bon     Mar 2006 Germany 2×1,481 Posts I've included a new page (available under menu 'Related' -> 'First SG'): It shows the first odd k-value where the numbers k*2n-1 and k*2n+1-1 are prime and therefore a Sophie-Germain pair. For now there're only values for n<=70 listed, others will follow. I've also created a DOS-batch to determine such values automatically: Code: @echo off set /a kval=%1 set /a nval=%2 :begin title k=%kval% n=%nval% echo 1:S:0:2:16394>SG.txt echo %kval% %nval% >>SG.txt cllr SG.txt if exist SG.res goto loop_nextn del llr.ini set /a kval=%kval%+6 goto begin :loop_nextn findstr /c:" " sg.res >>found.txt del sg.res sg.txt llr.ini lresults.txt set /a nval=%nval%+1 set /a kval=3 goto begin Name this batch 'run.bat'. To run this batch, cllr.exe (available from J.Penné, developer of LLR V3.8.1) is needed, too. Calling this script with run start_k start_n with start_k the k-value and start_n the n-value to start with, will search for a Sophie-Germain pair for n=start_n beginning at k=start_k and further ones (CTRL-C will stop this script). After stopping the batch, it can be restarted with the pair given in the file SG.txt (saved during the last run). Every found k/n-pair will be written to the file 'found.txt'. Note: Starting with start_n < 3 will give the false result for n=2, because the script starts always at k=3 (and incement the k-value by 6 -> only possible values for SG's). Perhaps others want to find some more ranges. Please post your results here. PS: I've changed the script to continue from a certain k-value. Last fiddled with by kar_bon on 2010-07-22 at 08:32
 2010-07-23, 18:06 #13 kar_bon     Mar 2006 Germany 2·1,481 Posts I've changed the above script, because it's timings were very lousy! Now I'm doing it this way: Code: @echo off set /a nval=%1 set /a kmin=1 set /a kmax=1000000 :begin title n=%nval% cnewpgen -wp=%nval%.txt -t=3 -base=2 -n=%nval% -kmin=%kmin% -kmax=%kmax% -own -osp=1000000000 >nul cllr -oStopOnSuccess=1 %nval%.txt >nul if exist %nval%.res goto loop_nextn if %kmin%==1 goto loop_nextk echo 0 %nval%>>%nval%.res goto loop_nextn :loop_nextk set /a kmin=1000000 set /a kmax=10000000 del llr.ini goto begin :loop_nextn findstr /c:" " %nval%.res >>found.txt del %nval%.txt %nval%.res llr.ini lresults.txt set /a kmin=1 set /a kmax=1000000 set /a nval=%nval%+1 goto begin To run this batch, cllr.exe and cnewpgen.exe are needed. Calling 'run 1' will start to search for a SG at n=1 and further until it will stopped (CTRL-C). Steps: - NewPGen will sieve for SG (base=2, n as above, kmin=1, kmax=1e6, pmax=1e9) - LLR will test the sieve file and stops when a SG was found - next n-value will tested automatically If for 1<=k<=1e6 no SG was found, the range 1e6<=k<=1e7 will be tested again. If this also fails to find a SG, the value "0 n-value" will be reported in 'found.txt'. This script took about an hour for n=1-430 (Q6600, 1 core, stock speed). I've also updated the new page with some more values. Last fiddled with by kar_bon on 2010-07-23 at 22:23
 2010-07-28, 00:38 #14 kar_bon     Mar 2006 Germany 296210 Posts I've submitted the above sequence to "The On-Line Encyclopedia of Integer Sequences" and can be found here.
 2010-10-06, 09:12 #15 kar_bon     Mar 2006 Germany 2×1,481 Posts Status 3rd Quarter 2010 8055 k-values (5+) 162942 primes (~1300+) 3457 twins (1+) 9532 Top5000-links (308+) Updated also Statistics and Riesel_all / Twins_all download files. Last fiddled with by kar_bon on 2010-10-06 at 09:13
 2010-10-17, 17:12 #16 kar_bon     Mar 2006 Germany 2·1,481 Posts Found doubled prime in C.Caldwell's Top5000 Database: 155*2^67973+1 (now deleted!) and 155*2^67973+1. Last fiddled with by kar_bon on 2010-10-17 at 17:56
 2011-04-21, 10:48 #17 kar_bon     Mar 2006 Germany 2×1,481 Posts I just noticed, that PrimeGrid found another Riesel-problem prime on 2011-04-05 (announcement here): 65531*2^3629342-1 is prime (1,092,546 digits, rank #29 on Top5000) There're 'only' 61 k-values left to proove the Riesel-conjecture.
 2011-05-12, 07:23 #18 kar_bon     Mar 2006 Germany 1011100100102 Posts A new Riesel-Prime seems to be found yesterday: 123547*2^3804809-1. The verification is still in progress. So (if it's a new one) 'only' 60 candidates left to proove the Riesel-Conjecture. PS: Verification done. Last fiddled with by kar_bon on 2011-05-12 at 13:41 Reason: Veri done
 2011-05-13, 23:49 #19 kar_bon     Mar 2006 Germany 2×1,481 Posts And here's the next Riesel Prime in sight: 415267*2^3771929-1 is still in progress (a little bit smaller than the last one). So 59 candidates left.
 2011-05-24, 19:53 #20 kar_bon     Mar 2006 Germany 2·1,481 Posts New page for RPS 2nd Megabit Drive included. Factors of Fermats and Generalized Fermats maked for k<=9 and some in 1000
 2011-05-29, 15:30 #21 kar_bon     Mar 2006 Germany 2×1,481 Posts The next Riesel Prime: 141941*2^4299438-1 is still in progress. So 58 candidates left.
 2011-06-01, 11:09 #22 kar_bon     Mar 2006 Germany 2·1,481 Posts Next Riesel Prime: 353159*2^4331116-1 just verifying. Now 57 candidates left.

 Similar Threads Thread Thread Starter Forum Replies Last Post gd_barnes No Prime Left Behind 255 2022-06-01 00:03 gd_barnes Conjectures 'R Us 304 2022-04-19 23:07 Cruelty Riesel Prime Search 41 2010-03-08 18:46 NBtarheel_33 Hardware 17 2009-05-04 15:52 KEP Riesel Base 3 Attack 4 2008-12-17 11:54

All times are UTC. The time now is 06:52.

Wed Jul 6 06:52:21 UTC 2022 up 83 days, 4:53, 0 users, load averages: 2.16, 1.50, 1.31