OFFSET
1,1
COMMENTS
The sequence admits only numbers with three distinct prime factors. A denser sequence (a superset) is obtained if prime factors may be repeated. [From R. J. Mathar, Oct 03 2010]
There is no term with four distinct prime factors under 10^8. [From Dmitri Kamenetsky, Sep 29 2012]
EXAMPLE
For 3311, 3311=7 * 11 * 43, and 71143, 74311, 43711, 43117, 11437, 11743 are all prime numbers.
MATHEMATICA
Take[Union[Times @@@ Select[Subsets[Prime[Range[300]], {3}], And @@ PrimeQ[FromDigits /@ (Flatten /@ (IntegerDigits /@ Permutations[#]))] &]], 30] (* Harvey P. Dale, Jan 29 2011 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
James Farrington, Sep 15 2010
EXTENSIONS
Missing values inserted by R. J. Mathar, Oct 03 2010
STATUS
approved