[seqfan] A068652 Numbers such that every cyclic permutation is a prime.

[Juan Arias de Reyna]

In the web page 

http://tangente-mag.com/maths_etonnantes.php?id=3139 <http://tangente-mag.com/maths_etonnantes.php?id=3139>

says that after the last number showed 319993 the only remaining terms
are the repunits  primes.  

Is this true?  Perhaps a comment to A068652 with this observation
should be added?

Juan