mersenneforum.org  

Go Back   mersenneforum.org > Prime Search Projects > Riesel Prime Search

Reply
 
Thread Tools
Old 2007-04-27, 21:28   #1
roger
 
roger's Avatar
 
Oct 2006

22×5×13 Posts
Default primes to expect per k?

I'm wondering how few n's a 'good' k should go through for 25, 50, 100 primes.

Thanks,

Roger
roger is offline   Reply With Quote
Old 2007-04-27, 21:47   #2
VBCurtis
 
VBCurtis's Avatar
 
"Curtis"
Feb 2005
Riverside, CA

10DF16 Posts
Default

Can you be more specific? Do you mean a k's first 25/50/100 primes? These numbers vary quite a bit, esp for first 25; there are k's that produce quite a few small primes, but not so many large primes (I no of no explanation for this).

It's easier to measure a k's weight/production by how many primes below n=100,000. You can count this yourself on our k<300 stats page, or read the threads about high-weight k's to see the fruit of a few members' search for the highest-weight k's around. Unfortunately, the very high-weight k's are also very large, which means LLR is slower per test. For instance, n=500k on k~3e9 took about the same amount of time as n=700k on k~100.

Weight and production of primes are not directly correlated, but they're close. Larry has a spreadsheet from over a year ago that studied this relationship (look for a thread titled something like "weight vs number of primes").

-Curtis
VBCurtis is offline   Reply With Quote
Old 2007-04-27, 22:04   #3
roger
 
roger's Avatar
 
Oct 2006

22·5·13 Posts
Default

Thanks, curtis

Yeah, I mean a k's first 25/50/100 primes. So far [I have been searching through small n's for 'good' k's] the best I've seen is 32 primes for 7000 n's with a 6-digit k. [worst is 8 primes for 10000 n's]

I'll have a look around, and BTW I also noticed that some k's produce many small primes and no large. That's primes for you...

Roger
roger is offline   Reply With Quote
Old 2007-04-28, 06:02   #4
robert44444uk
 
robert44444uk's Avatar
 
Jun 2003
Oxford, UK

3·54 Posts
Default

The best I have managed at 25/50/75/100 primes are 56/294/1254/3258, all for + series.

More detail:

10 primes/n=10
20/37
30/83
40/173
50/294
60/550
70/847
80/1599
90/1951
100/3258
110/4495
120/12950
130/19593
140/52310
150/122428
160/202474
170 no k found
robert44444uk is offline   Reply With Quote
Old 2007-04-29, 04:29   #5
roger
 
roger's Avatar
 
Oct 2006

10416 Posts
Default

Robert, Thanks for the numbers, they'll come in handy for when I have something to relate to them!

Roger
roger is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Distribution of Mersenne primes before and after couples of primes found emily Math 34 2017-07-16 18:44
Do you expect team sub forums to be wiped clean after game ends? Raman Chess 10 2016-11-11 17:28
What to expect from GTX1080 for ECM? fivemack GPU Computing 10 2016-05-11 09:07
What Murphy score to expect or need [cado-nfs] kosta Factoring 3 2013-04-17 17:30
How much should one expect to pay for a used/refurb. macbook? ewmayer Lounge 6 2013-01-23 19:45

All times are UTC. The time now is 12:28.

Thu Sep 24 12:28:37 UTC 2020 up 14 days, 9:39, 0 users, load averages: 2.09, 1.82, 1.79

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.