A180679 Numbers with three distinct prime factors which when concatenated in any order form prime numbers.

3311, 27181, 32153, 41237, 53977, 86507, 110971, 125069, 208579, 256413, 500981, 543337, 853811, 901949, 964481, 1053787, 1144171, 1197851, 1215731, 1344539, 1385189, 1433659, 1549603, 1674741, 1681547, 1699481, 1973479, 2028181

Offset: 1

Author

James Farrington, Sep 15 2010

Keywords

• nonn
• base

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]

Examples

			For 3311, 3311=7 * 11 * 43, and 71143, 74311, 43711, 43117, 11437, 11743 are all prime numbers.
		

Crossrefs

Cf. A181559, A217263, A217264, A217265.

Programs

Mathematica

Take[Union[Times @@@ Select[Subsets[Prime[Range[300]], {3}], And @@ PrimeQ[FromDigits /@ (Flatten /@ (IntegerDigits /@ Permutations[#]))] &]], 30] (* Harvey P. Dale, Jan 29 2011 *)

Extensions

Missing values inserted by R. J. Mathar, Oct 03 2010