Re: A stronger fact holds ? ( was: p Mersenne => p^2-p+1 non-prime ? )
- From: "Anvita" <anvita21@xxxxxxx>
- Date: 14 Jun 2005 02:56:24 -0700
Gerry Myerson писал(а):
> In article <1118646412.078921.210610@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
> "Anvita" <anvita21@xxxxxxx> wrote:
>
> > *
> > * For every prime t > 3, the number
> > * p(p-1)+1 is composite, where p = 2^t-1.
> > *
> >
> > It can be shown that if t =/= 1 mod 12
> > then p(p-1)+1 is composite, so we only need
> > to consider t == 1 mod 12.
> > I checked this on a computer for t < 1000.
> > No counterexample.
> >
> > However, if t = 25 then p(p-1)+1 is "probably" prime
> > according to GAP.
>
> Maple confirms that this number, 1125899806179331, is prime.
>
Unfortunately, this does not disprove the conjecture,
since the exponent 25 is not prime.
Anvita
.
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- A stronger fact holds ? ( was: p Mersenne => p^2-p+1 non-prime ? )
- From: Anvita
- Re: A stronger fact holds ? ( was: p Mersenne => p^2-p+1 non-prime ? )
- From: Gerry Myerson
- A stronger fact holds ? ( was: p Mersenne => p^2-p+1 non-prime ? )
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