A181559 Numbers with three distinct prime factors (each of which may or may not be repeated) which when concatenated in any order form a prime number.

3311, 23177, 27181, 32153, 36421, 41237, 53977, 86507, 110971, 125069, 142373, 162239, 190267, 208579, 254947, 256413, 288659, 298991, 353683, 377839, 400631, 500981, 543337, 593747, 769239, 776797, 853811, 875483, 901949, 964481, 996611, 1053787, 1135673

Offset: 1

Author

Harvey P. Dale, Jan 29 2011

Keywords

• nonn
• base

Comments

This is a superset of A180679 because in this sequence, unlike in A180679, any of the prime factors may (but need not) be repeated as a factor.

Crossrefs

Cf. A180679, A217263, A217264, A217265.

Programs

Mathematica

okQ[n_] := Module[{pfs = Transpose[FactorInteger[n]][[1]]}, Length[pfs] == 3 && And @@ PrimeQ[FromDigits /@ (Flatten /@ (IntegerDigits /@ Permutations[pfs]))]]; Select[Range[2100000], okQ]