Re: [PrimeNumbers] Are these prime?
- --- Roahn Wynar <rwynar@...> wrote:
> Hello all,odd+/-1 = even
> I have run accross the need to determine which, if any, of the following
> eight numbers are prime:
> 3^30 +/- 1
> 3^29 +/- 1
> (3^27 x 4 ) +/- 1Grab GP/Pari, it'll tell you in a trice.
> (3^27 x 8 ) +/- 1= ((3^9*2)^3) +/-1
= cube +/-1
x^3+1 = (x+1)(x^2-x+1)
x^3-1 = (x-1)(x^2+x+1)
> I am not able to make the determination right now myself but I am workingFactoring anything under 60 digits is almost always instant.
> hard to learn more advance factorization methods. I don't even have a good
> sense of whether making the above primality determinations would be easy or
> hard given the current state of the art. If anyone happens to have handy
> answers I would be grateful, but I certainly do not expect anyone to make any
> significant computation (if that is what it takes) on my behalf.
Primality testing anything under 500 digits is almost always instant.
() ASCII ribbon campaign () Hopeless ribbon campaign
/\ against HTML mail /\ against gratuitous bloodshed
[stolen with permission from Daniel B. Cristofani]
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around