20160422, 21:18  #1 
"Jason Goatcher"
Mar 2005
5×701 Posts 
k*b^n+/c where b is an integer greater than 2 and c is an integer from 1 to b1
I don't have the mathematical ability to discuss this, but talking to Xyzzy tickled my brain in a way that made me remember a friend from years ago talking about this.
Basically, and I'll try to be as rigorously technical as possible, the idea is that k*b^n+/c might be able to be tested with b equaling an integer higher than 2 WITHOUT referring to methods used for a simple string of digits. In other words, if my friend was correct(someone other than Xyzzy, he just managed to remind me of it) than there are mathematical shortcuts to testing k*b^n+/c with b equaling integers greater than 2 and c equaling integers other than 1, but also occasionally including 1(for the oddnumbered b's) Following is the idea for the equation my friend talked about. He was way over my head with the concepts, but was involved with jjsieve. I'm intentionally being vague about his identity because he likes his privacy, so please don't openly state his real name on here, but a bit of research and talking to jasonp, if he's still on here, should reveal more information. Jasonp is very bright in his own right but, while he is the public face of jjsieve, is not the only one involved. The math came from elsewhere. Not sure if the source code for jjsieve is publicly available. If it is, and you have both the programming skills(enough to comprehend the code, if not duplicate it) and the math skills to understand complex sieving code, you might strongly benefit from giving it a look. Below is simply a copy of what is in the title, since unnecessary scrolling sucks. k*b^n+/c where b is an integer greater than 2 and c is an integer from 1 to b1 Byes. 
20160422, 21:31  #2  
If I May
"Chris Halsall"
Sep 2002
Barbados
9286_{10} Posts 
Quote:
Someone's time. Do you have a specificity important point to reciprocate? Last fiddled with by chalsall on 20160422 at 21:38 

20160423, 11:15  #3 
Jun 2003
17×277 Posts 
Are you saying that if one studies jjsieve source, one will find a new method to test numbers of the form k*b^n+/c?

20160423, 16:49  #4 
"Forget I exist"
Jul 2009
Dumbassville
8,369 Posts 
maybe I'm missing something why is c limited to 1 to b1 ? I can figure b^n1 as the upper limit I can see k semi being limited to 1 to b1 if you allow c to possibly go over that limit though.
you can sieve out a lot depending on what you do to sieve but most if not all have a thread that talks about them. 
20160423, 18:29  #5 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
10001110100100_{2} Posts 
I am not sure people usually think about these things but I suppose this place to cast them is as good as any:

20160424, 03:40  #6 
Aug 2006
2^{3}×3×13×19 Posts 

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