Composite being Prime
 

Hey,

why is FactorDB refusing a primality certificate on [url=http://factordb.com/index.php?query=23801%23%2B1]23801#+1[/url] and why does it think that this number is composite? I found others examples in the past but could not find them again in the moment. :|
Looking at [URL="http://mathworld.wolfram.com/PrimorialPrime.html"]MathWorld[/URL], it is already a proven prime, so I have no doubts in this (especially after I did a certificate with primo).

Greetings,
Oliver!

It is a known issue of FactorDB's handling of "#". :smile:

[QUOTE=paulunderwood;480134]It is a known issue of FactorDB's handling of "#". :smile:[/QUOTE]

I'm aware of the issue of handling ## (because PFGW doesn't know ##). Didn't know that there was one for #?!

[QUOTE=axn;480159]I'm aware of the issue of handling ## (because PFGW doesn't know ##). Didn't know that there was one for #?![/QUOTE]

You are probably right, but if you click on "number" field on [url]http://factordb.com/index.php?query=23801%23%2B1[/url] you get 1+2647##

[QUOTE=paulunderwood;480179]You are probably right, but if you click on "number" field on [url]http://factordb.com/index.php?query=23801%23%2B1[/url] you get 1+2647##[/QUOTE]

Aha! So factordb understands that number with ## representation, and PFGW checked 2647#+1, which is a composite. Mystery solved.

Syd needs to find all numbers with an internal ## representation and fix it. Probably not gonna happen anytime soon.

[QUOTE=axn;480184]Aha! So factordb understands that number with ## representation, and PFGW checked 2647#+1, which is a composite. Mystery solved.

Syd needs to find all numbers with an internal ## representation and fix it. Probably not gonna happen anytime soon.[/QUOTE]
I'm up to four known ## candidate PRPs below 4xxx dd. I have my scripts skip them.