20181012, 15:47  #430 
"Curtis"
Feb 2005
Riverside, CA
1000001110001_{2} Posts 
May I reserve the Primo run to verify primality of the M51487 cofactor?

20181012, 16:44  #431 
Sep 2003
A12_{16} Posts 

20181012, 16:58  #432  
Jun 2003
11×421 Posts 
Quote:


20181012, 17:54  #433  
Sep 2003
2×1,289 Posts 
Quote:
I compared Chris Caldwell's list of Mersenne PRP cofactors, where the largest is not quite 20,000 digits, and his list of generalized repunit PRPs, where the digit lengths go up to 95,000 digits. The generalized repunit PRPs in the list all have large b, in the thousands or tens of thousands. Nearly all of the primality certificates are by Tom Wu. Is it somehow generally true that for larger b it is easier to prove primality of (b^{p} − 1) divided by some divisor? And perhaps easier to find PRPs in the first place? However, looking at the Lifchitz list of top PRPs, however, the top 1 and 2 are Wagstaff (repunit with b=−2), numbers 4, 5, 6, 8 and 14 are Mersenne cofactors (repunit with b=2), number 11 is a repunit PRP with b=−13, number 12 is a repunit PRP with b=5, etc. I don't see any large b bases in the top rankings. 

20181012, 19:06  #434  
Sep 2002
Database er0rr
2^{2}·19·43 Posts 
Quote:


20181012, 20:29  #435  
"Serge"
Mar 2008
Phi(3,3^1118781+1)/3
5×1,811 Posts 
Quote:
so if p1 is fairly smooth, and some of the cofactors happen to be prime, then you have a path to N1 proof. Same for N+1. What we see at the top https://primes.utm.edu/top20/page.php?id=16, are enriched with harder proof methods but if you use https://primes.utm.edu/primes/search.php, and search for Text Comment = Generalized Repunit, Type = all, Maximum number of primes to output = 2000, you will find tons of simple N+1 proofs, as well. 

20181013, 16:38  #436 
"Curtis"
Feb 2005
Riverside, CA
3·23·61 Posts 
It has been a while since I've used Primo; I forgot that it lacks commandline interface, and I have only SSH access to my 40thread workstation. I should put some time into relearning Primo usage on smaller inputs before I tackle a multimonth job; unreserving this cofactor.

20181013, 17:06  #437 
"Serge"
Mar 2008
Phi(3,3^1118781+1)/3
5×1,811 Posts 

20181013, 17:38  #438 
Sep 2003
101000010010_{2} Posts 
Has anyone tried the primecert and primecertexport functions in recent PARI/GP versions? The documentation says it can create a Primo v. 4 certificate. How does the speed compare with the actual Primo program?

20181023, 14:18  #439 
Aug 2002
Buenos Aires, Argentina
1,319 Posts 
I was able to configure Bash for Windows to run Primo on Windows 10.
I performed the following steps in Ubuntu 18.04 on Bash for Windows: 1) Install Xming (the X server) 2) Open Bash for Windows 3) Type sudo aptget update 4) Type sudo aptget upgrade 5) Type sudo aptget install gdkpixbuf2.00 6) Type sudo aptget install libgtk2.0dev 7) Type sudo aptget install xdgutils 8) Open .bashrc (I used nano), add the following line at the end of this file: export DISPLAY=:0 and save it. 9) Download the latest version of Primo and decompress it in a directory that can be seen on Bash for Windows 10) Close Bash for Windows 11) Ensure that Xming is running 12) Open Bash for Windows 13) Run Primo and enjoy. 
20181105, 02:38  #440 
Sep 2002
Database er0rr
2^{2}×19×43 Posts 
Congrats for the proof. https://primes.utm.edu/primes/page.php?id=125757
Last fiddled with by paulunderwood on 20181105 at 02:39 
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