mersenneforum.org  

Go Back   mersenneforum.org > Factoring Projects > Factoring

Reply
 
Thread Tools
Old 2005-08-18, 09:49   #1
penguinman007
 
Aug 2005

22 Posts
Lightbulb Factor me this

e.g Can someone tell me if the following number is prime (or how do I find out for myself):

(2 ^ 65536) + 1


Penguinman007
penguinman007 is offline   Reply With Quote
Old 2005-08-18, 10:58   #2
jinydu
 
jinydu's Avatar
 
Dec 2003
Hopefully Near M48

2×3×293 Posts
Default

This question was already posted in the Soap Opera
jinydu is offline   Reply With Quote
Old 2005-08-18, 16:00   #3
akruppa
 
akruppa's Avatar
 
"Nancy"
Aug 2002
Alexandria

2,467 Posts
Default

...but better fits into the Factoring forum.
This is the 16-th Fermat number. The small Fermat numbers have received great factoring efforts already, discovering new factors will be very hard. Use Google or the Forum search to find out more.

Alex
akruppa is offline   Reply With Quote
Old 2005-08-18, 20:33   #4
sean
 
sean's Avatar
 
Aug 2004
New Zealand

13·17 Posts
Default

No it is not prime. We can tell you this without exhibiting a factor.
sean is offline   Reply With Quote
Old 2005-08-21, 11:19   #5
ATH
Einyen
 
ATH's Avatar
 
Dec 2003
Denmark

1011110000012 Posts
Default

http://www.prothsearch.net/fermat.html

As you can se under F16 there is 2 known factors 825753601 and 188981757975021318420037633 but there is still a 19694 digit number left that is composite.
ATH is online now   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
A new factor of F11?! siegert81 FermatSearch 2 2018-01-24 04:35
What a (TF) factor!!... lycorn PrimeNet 11 2013-01-12 12:07
New factor for F17 Buckle Factoring 15 2011-03-15 12:05
Bad Factor? nfortino Data 6 2004-12-14 19:25
Shortest time to complete a 2^67 trial factor (no factor) dsouza123 Software 12 2003-08-21 18:38

All times are UTC. The time now is 22:14.

Thu Jan 21 22:14:33 UTC 2021 up 49 days, 18:25, 0 users, load averages: 2.77, 2.73, 2.50

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.