mersenneforum.org infinite mersenne prime numbers
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 2021-02-22, 01:32 #1 murzyn0   Feb 2021 3 Posts infinite mersenne prime numbers 2^p - 1, where p is prime number is always prime number, for example: 2^7 - 1 is 127, 2^127 - 1 is 170141183460469231731687303715884105727, 2^170141183460469231731687303715884105727 - 1 is big number, but its prime number, so it's eveidnce that there is infinity mersenne prime numbers
 2021-02-22, 01:52 #2 paulunderwood     Sep 2002 Database er0rr E2D16 Posts https://primes.utm.edu/mersenne/index.html#unknown Proving a ~10^51217599719369681875006054625051616349 digit number prime is beyond all known technolgy. Last fiddled with by paulunderwood on 2021-02-22 at 01:54
2021-02-22, 01:56   #3
Batalov

"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

2×37×127 Posts

Quote:
 Originally Posted by murzyn0 2^p - 1, where p is prime number is always prime number
Really?
So if p=11 is a prime number, then 2^11-1 "is always prime number"?

 2021-02-22, 01:59 #4 Uncwilly 6809 > 6502     """"""""""""""""""" Aug 2003 101×103 Posts 22·53·19 Posts
 2021-02-22, 11:20 #5 M344587487     "Composite as Heck" Oct 2017 7×113 Posts Unfortunately you forgot to end with QED so the proof is inadmissible.
2021-02-22, 19:48   #6
murzyn0

Feb 2021

3 Posts

Quote:
 Originally Posted by Batalov Really? So if p=11 is a prime number, then 2^11-1 "is always prime number"?
My bad, p must be always result of mersenne prime numbers.

2021-02-22, 21:03   #7
paulunderwood

Sep 2002
Database er0rr

19×191 Posts

Quote:
 Originally Posted by murzyn0 My bad, p must be always result of mersenne prime numbers.
2^13-1== 8191 is prime. 2^8191-1 is not. Easy to check.

2021-02-22, 21:33   #8
murzyn0

Feb 2021

112 Posts

Quote:
 Originally Posted by paulunderwood 2^13-1== 8191 is prime. 2^8191-1 is not. Easy to check.

but, 13 in 2^13-1 is not a mersenne prime numbers.

2^p - 1, where p is a mersenne prime, yields a different mersenne prime.

2021-02-22, 21:39   #9
Viliam Furik

"Viliam Furík"
Jul 2018
Martin, Slovakia

6778 Posts

Quote:
 Originally Posted by murzyn0 but, 13 in 2^13-1 is not a mersenne prime numbers. 2^p - 1, where p is a mersenne prime, yields a different mersenne prime.
But that's not proven. And no, 3 examples are not proof.

 2021-02-22, 21:52 #10 Dr Sardonicus     Feb 2017 Nowhere 7·641 Posts MODERATOR NOTE: Thread closed.
2021-02-23, 03:19   #11
retina
Undefined

"The unspeakable one"
Jun 2006
My evil lair

24×383 Posts

Quote:
 Originally Posted by murzyn0 2^p - 1, where p is prime number is always prime number, for example: 2^7 - 1 is 127, 2^127 - 1 is 170141183460469231731687303715884105727, 2^170141183460469231731687303715884105727 - 1 is big number, but its prime number, so it's eveidnce that there is infinity mersenne prime numbers
Eveidnce [sic] != proof.
Quote:
 Originally Posted by murzyn0 but, 13 in 2^13-1 is not a mersenne prime numbers. 2^p - 1, where p is a mersenne prime, yields a different mersenne prime.
2^5-1 (=31) is prime. 2^31-1 is prime. But 2^(2^31-1)-1 is composite, factors are known.

How back to you go? Because 5 is not a Mersenne prime. And your example above, 2 is not a Mersenne prime either, so the sequence 2, 3, 7, 127, ... doesn't start with a Mersenne prime.

And if you conveniently ignore the first term then 3, 7, 127, ... does match your claim, but then 31, 2147483647, ... fails your claim. You can't have it both ways.

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