Corrected On sequence nXn where x equal 09,18,27,36,45,54,63,72,81,90

[bouyao]

Dear Richard,
you have right and thanks for you information.

I analyzed all prime numbers p such that
p is prime
pnp is prime
and n has two digits between 01 .. 99

I remark that there are
no prime numbers between 10^5 , 10^6 for p07p
no prime numbers betwen 10^6, 10^7 for p14p
no prime numbers betwen 10^7, 10^8 for p21p
...
no prime numbers betwen 10^5, 10^6 for p85p

there are anothers numbers that have this remark (p11p,...)

Why certains numbers have this remark ?

thanks.

(je m'explique en français que si on trace la courbe pnp
tout les multiples de 3 se trouvent dans une même region et les autres dans
d'autres régions et que pour certains nombres il y a un grand Saut exemples
07,14,21 ,.. et 11,22, ..mais pas de saut pour 03,..)





----- Original Message ----- 
From: "Richard Guy" <rkg at cpsc.ucalgary.ca>
To: "Karima MOUSSAOUI" <bouyao at wanadoo.fr>
Cc: <seqfan at ext.jussieu.fr>
Sent: Wednesday, February 25, 2004 6:51 AM
Subject: Re: Corrected On sequence nXn where x equal
09,18,27,36,45,54,63,72,81,90


> These will form an AP with common diff 90 or 900 or
> 9000 or  ..., one member of which will be divisible by 7.  R.
>
> On Mon, 23 Feb 2004, Karima MOUSSAOUI wrote:
>
> > Dear Seqfna,
> > Can anyone find n such that n09n,
n18n,n27n,n36n,n45n,n54n,n63n,n72n,n81n,n90n, are all primes
> > where n09n designe concatenation of (n 09 n) (example 1091 is prime,
310931 is prime)
> > Thanks
> > M.Bouayoun
>