20040618, 07:34  #1 
2^{3}×263 Posts 
How to check if a number is a Mersenne prime ?
What do I do if I think I have found a greater mersenne but my calculator has no way to check it, or I don't. (It can only do 2^400 or something...)
Is there a fairly easy way to check whether I have one or not with a program? I tried downloading 'ntprime' but I don't know how it works, it didn't seem to do anything... 
20040618, 09:20  #2 
Dec 2003
Paisley Park & Neverland
5×37 Posts 
A Mersenne number (> just check if the exponent is prime) or a Mersenne prime? For the latter: download Prime95 Version 23.8 from http://www.mersenne.org/freesoft.htm and enter the exponent in [Prime95]>[Advanced]>[Test]. If you don't see immedite progress just lower the entry in [Prime95]>[Options]>[Preferences]>[Iterations between screen outputs].
Prime95 works for exponents up to 79 300 000. MrHappy. 
20040618, 13:37  #3  
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
3^{2}·1,021 Posts 
You can find a list of all known Mersenne primes here: http://www.utm.edu/research/primes/m...dex.html#known
Also, know that: Quote:


20040618, 16:14  #4 
5,569 Posts 
that's what u think!!

20040618, 20:40  #5 
Sep 2003
Borg HQ, Delta Quadrant
2·3^{3}·13 Posts 
I think our tests are fairly conclusive. We keep testing the exponent until we get two matching residues. Version 23 implements error codes so we can tell if a test is probably bad.

20040618, 20:55  #6 
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
3^{2}×1,021 Posts 
Yes, I think that the matching residues is key here. To have these 2 large numbers to happen to match and one be an erroneous test is highly unlikely. To have 2 that have errors that match is so unlikely that it is considered to be all but magical. The actual chances are around.
Having a second type of hardware with a second program check this with the same residue is considered proof for the math community. 
20040619, 08:18  #7 
2·3·1,049 Posts 
Ok I had the wrong program before, that one worked, thanks.
I was attemptimng one much higher than 8 mil, more like 54 million or something but it wasn't even a prime number so no luck... Thanks anyway. 
Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
(M48) NEW MERSENNE PRIME! LARGEST PRIME NUMBER DISCOVERED!  dabaichi  News  571  20201026 11:02 
How to Check if NonMersenne Number isPrime?  FloatingPoint  Operation Billion Digits  39  20151021 02:15 
Number of distinct prime factors of a Double Mersenne number  aketilander  Operazione Doppi Mersennes  1  20121109 21:16 
mersenne prime as a factor of another number  kurtulmehtap  Math  21  20101108 18:21 
Probability of a Mersenne number being prime  vimil  Information & Answers  13  20071212 11:21 