Go Back > New To GIMPS? Start Here! > Information & Answers

Thread Tools
Old 2014-12-19, 14:11   #1
Jul 2014

1BF16 Posts
Default probabilty of finding a mersenne prime


when I get some assignments from the GIMPS server I get an approximate
probabilty of finding a MP.

Does anyone know how the odds are worked out.

My guess is that it uses the PNT.

wildrabbitt is offline   Reply With Quote
Old 2014-12-19, 16:26   #2
Account Deleted
Mini-Geek's Avatar
"Tim Sorbera"
Aug 2006
San Antonio, TX USA

17×251 Posts
Default mentions this at the end of the LL section.
This simplifies to 64 / 5000070 or 1 in 78126. This simple approach isn't quite right. It would give a formula of how_far_factored divided by (exponent divided by 2). However, more rigorous work has shown the formula to be (how_far_factored-1) / (exponent times Euler's constant (0.577...)). In this case, 1 in 91623. Even these more rigourous formulas are unproven.
Mini-Geek is offline   Reply With Quote
Old 2014-12-19, 19:15   #3
Jul 2014

3·149 Posts

wildrabbitt is offline   Reply With Quote
Old 2014-12-19, 20:50   #4
P90 years forever!
Prime95's Avatar
Aug 2002
Yeehaw, FL

22×1,873 Posts

Prime95 also assumes if P-1 has been run it had a 3 or 4% chance of finding a factor (I'd have to look at the code). This improves your chances that the LL test will show the Mersenne number to be prime.
Prime95 is online now   Reply With Quote

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Maximize chances of finding Mersenne Prime dennisonprime Information & Answers 7 2016-11-10 07:52
How close have you been to finding a Mersenne prime? NBtarheel_33 Data 42 2013-07-17 19:21
Finding the square root of a large mersenne number Fusion_power Math 29 2010-10-14 17:05
probability of finding a Mersenne prime optim Math 2 2003-12-06 19:03
yapp - yet another probabilty problem graeme Puzzles 15 2003-08-03 20:34

All times are UTC. The time now is 04:32.

Sat May 15 04:32:40 UTC 2021 up 36 days, 23:13, 0 users, load averages: 2.07, 2.09, 2.16

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, 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.