20150325, 23:44  #1 
"J. Gareth Moreton"
Feb 2015
Nomadic
132_{8} Posts 
What makes a prime worth mentioning?
I want to test my coding efficiency in prime number checking and generation, including ones of more unusual or arbitrary constructions (e.g. ones that can be decoded to reveal images and messages, for example).
My question is... how large should a prime number be to be considered worth posting here? 
20150326, 02:12  #2 
Account Deleted
"Tim Sorbera"
Aug 2006
San Antonio, TX USA
17×251 Posts 
If its most notable feature is its size, then I'd base it off of the smallest numbers on one of these standard lists, based on its type:
Any prime that doesn't fit these criteria, but that you think may be interesting to others for some other reason, could also be posted. Software, especially if it can compete with the common standard prime searching tools (Prime95, PFGW, etc.) would also be interesting. An example of primes that would not be interesting/good to post is ones that can be discovered trivially with standard tools and are not otherwise interesting, whether your software took weeks or seconds to find them. Primes that can be decoded into images/messages could fall into either category, depending on what you're encoding, if you have a generalized way to encode them, and if you want to spam every random image or message you can find, or just interesting ones (or post the techniques you use to make them, so people can generate their own spam if they like). On the topic of embedding messages in primes, you will probably find this interesting: https://en.wikipedia.org/wiki/Illegal_prime All just my opinions. Last fiddled with by MiniGeek on 20150326 at 02:17 
20150326, 02:21  #3 
Romulan Interpreter
Jun 2011
Thailand
8,963 Posts 
Say, over a million digits?
And if it is not an illegal prime... Edit, grrrr... that guy was faster... Last fiddled with by LaurV on 20150326 at 02:22 
20150326, 02:34  #4 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
21737_{8} Posts 

20150326, 02:52  #5 
Romulan Interpreter
Jun 2011
Thailand
8,963 Posts 
Well.. actually... if you put it like that, the only primes worth mentioning and be posted here are the primes which are part of encryption keys for bank accounts. Post them here together with the account name, bank, etc... whatever may be necessary...

20150326, 06:07  #6 
Undefined
"The unspeakable one"
Jun 2006
My evil lair
5889_{10} Posts 
In that line of thought then all you'd need are the prime factors of the signing keys. After that everything else is a doddle.

20150326, 11:39  #7 
"J. Gareth Moreton"
Feb 2015
Nomadic
90_{10} Posts 
The article on illegal primes is what caught my attention, I confess!
Hmmm, and some of these numbers may take some time to generate. Thanks for the response chaps  I'll see what I can come up with. 
20150326, 22:27  #8 
"Jane Sullivan"
Jan 2011
Beckenham, UK
3×79 Posts 
The article on illegal primes caught my attention too. The whole thing is bloody silly? How paranoid can the republicans get?
I have a collection of prime numbers. If one of these socalled "illegal" primes appears in that collection, I neither know nor care. If I receive a letter from some lawyer insisting I delete one of those numbers (cease and desist or whatever it is called) I shall ensure that letter goes viral on social media before ceremonially burning it. What makes a prime worth mentioning? I don't know. Is 2 worth mentioning? (Answer  probably, yes, because it's the only even prime), or 2,147,483,647? or any other that you might think of? 
20150327, 00:15  #9 
"J. Gareth Moreton"
Feb 2015
Nomadic
2·3^{2}·5 Posts 
Well, that's the nice thing about numbers... they can't be copyrighted or censored in their pure form. So if it just so happens to also represent a valid compressed archive that contains the C source code to a DVD decoder, that's their problem!
Of course, there can still be a danger of harassment or worse upon the disclosure of a BluRay master key or if you generate a prime number that happens to be one of the prime factors of an important RSA key pair (which is incredibly unlikely... usually the sign of the key issuer having a poor random number generator). 
20150327, 00:28  #10  
Undefined
"The unspeakable one"
Jun 2006
My evil lair
3×13×151 Posts 
Quote:


20150425, 17:56  #11 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
3·3,061 Posts 
Here is a couple of (PRP) prime partition numbers that are unusually close together:
numbpart(1234626973) and numbpart(1234631715) Is it worth mentioning? I think, maybe. 
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