mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Data > mersenne.ca

Reply
 
Thread Tools
Old 2016-06-19, 19:29   #45
GP2
 
GP2's Avatar
 
Sep 2003

258510 Posts
Default

Quote:
Originally Posted by axn View Post
Obviously, this doesn't involve factoring the composite factor's k -- that part is very much useless.
It's not entirely useless.

Every factor of a Mersenne number is of the form q = 2kp + 1, so q−1 = 2kp. Here "q" is the "P" of the P−1 factorization method, so displaying the factorization of k tells you at a glance how powersmooth q−1 is.

You can see at a glance (after the fact, of course) what the smallest bounds of B1 and B2 would have been for finding that factor with the P−1 method. So you could often distinguish at a glance how likely it was that the factor was found with P−1, as opposed to ECM or TF.
GP2 is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
ECM on small Mersenne Numbers Erich PrimeNet 16 2012-09-29 23:08
Can two Mersenne numbers share a factor? James Heinrich Math 57 2011-09-12 14:16
mersenne prime as a factor of another number kurtulmehtap Math 21 2010-11-08 18:21
Mersenne factor bitblit Math 3 2009-05-02 01:20
Fast calculations modulo small mersenne primes like M61 Dresdenboy Programming 10 2004-02-29 17:27

All times are UTC. The time now is 05:31.


Mon Oct 25 05:31:48 UTC 2021 up 94 days, 47 secs, 0 users, load averages: 0.85, 0.96, 1.04

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.