mersenneforum.org The 40th known Mersenne prime, 220996011-1 is not PRIME!
 User Name Remember Me? Password
 Register FAQ Search Today's Posts Mark Forums Read

 2004-02-27, 03:39 #1 illman-q   Feb 2004 Sydney 7 Posts The 40th known Mersenne prime, 220996011-1 is not PRIME! Hello I am very new to this but to a person that is no mathamatician, when I look at the short representation of the large Mersenne Prime, I see a -1 at the end. Now if thats what you have to do to the actually number, subtract 1 to make it a prime them the above mentioned number is NOT A PRIME. I am probably illinformed and wrong with the calculations but thats what I did and then divided it with a certain number and found it to be divisible by it. Can anyone please enlighten me of what is right or wrong? I told you i was very new!(hehehahah)
 2004-02-27, 07:58 #2 outlnder     Aug 2002 2·3·53 Posts The actual number is 2 to the 20996011 power minus 1.
 2004-02-27, 15:09 #3 Uncwilly 6809 > 6502     """"""""""""""""""" Aug 2003 101×103 Posts 3×19×151 Posts Yes, it is (220996011)-1 which is about 6.5 million digits long. The number is not 220996011-1 (which is even), nor is it (2 X 20996011)-1, nor even 220996011-1.
2004-02-28, 04:17   #4
illman-q

Feb 2004
Sydney

7 Posts
NO JOKE

Quote:
 Originally Posted by Uncwilly Yes, it is (220996011)-1 which is about 6.5 million digits long. The number is not 220996011-1 (which is even), nor is it (2 X 20996011)-1, nor even 220996011-1.
NO JOKE its over 6 million digits. I downloaded the 6 million+ digits and thats what was subtracted by 1 and got a multiple of a certian number that I used.

Last fiddled with by illman-q on 2004-02-28 at 04:20

 2004-02-28, 05:07 #5 dave_0273     Oct 2003 Australia, Brisbane 7268 Posts Well, then - what is the factor????
2004-02-28, 05:13   #6
nfortino

Nov 2003

101001012 Posts

Quote:
 Originally Posted by illman-q NO JOKE its over 6 million digits. I downloaded the 6 million+ digits and thats what was subtracted by 1 and got a multiple of a certian number that I used.
Is this to say you to the 6 million digit file, and subtracted 1, and found factors of that number? If so, then you were factoring 2^20966011-2, which has many factors (one of them being 2). The file you downloaded already has the -1 in it, so you can't subtract one again.

2004-02-28, 08:44   #7
Pablo the Duck

Dec 2003
Team China

2·33 Posts

Quote:
 Originally Posted by dave_0273 Well, then - what is the factor????
I reckon his "factor" is 2.

2004-02-28, 22:07   #8
Maybeso

Aug 2002
Portland, OR USA

2·137 Posts

Quote:
 Originally Posted by nfortino ...If so, then you were factoring 2^20966011-2, which has many factors (one of them being 2). The file you downloaded already has the -1 in it, so you can't subtract one again.
2^20966011-2 = 2(2^20966010-1), 20966010 = 2*3*5*13*53759 -->
= 2(2^10483005-1)(2^10483005+1)
= 2(2^3494335-1)(2^6988670 + 2^3494335 + 1)(2^3494335+1)(2^6988670 - 2^3494335 + 1)
= ...

hmm, my binomial expansion skills are a bit rusty ... anyway, his factor is in there, but I vote for '2' as well.

 2004-02-29, 19:32 #9 ixfd64 Bemusing Prompter     "Danny" Dec 2002 California 8FF16 Posts Sounds like fame-bait to me...
2004-03-02, 02:50   #10
illman-q

Feb 2004
Sydney

7 Posts
The fctor is 19 no Fame seeking factor!

Quote:
 Originally Posted by ixfd64 Sounds like fame-bait to me...
Not an actor a factor of 19!

Last fiddled with by illman-q on 2004-03-02 at 03:00

 2004-03-04, 02:26 #11 ixfd64 Bemusing Prompter     "Danny" Dec 2002 California 8FF16 Posts Oops, meant to say "flame-bait"... Last fiddled with by ixfd64 on 2004-03-04 at 02:27

 Similar Threads Thread Thread Starter Forum Replies Last Post dabaichi News 561 2013-03-29 16:55 Brain PrimeNet 3 2010-07-22 10:01 Citrix Lounge 28 2003-12-21 19:42 Unregistered Software 7 2003-12-05 09:12 raucourt Lounge 3 2003-12-04 16:35

All times are UTC. The time now is 05:54.

Thu Sep 24 05:54:55 UTC 2020 up 14 days, 3:05, 0 users, load averages: 1.81, 1.44, 1.32