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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. 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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.

LINKS

Table of n, a(n) for n=1..33.

MATHEMATICA

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

CROSSREFS

Cf. A180679, A217263, A217264, A217265.

Sequence in context: A320717 A106724 A239671 * A180679 A251900 A078348

Adjacent sequences:  A181556 A181557 A181558 * A181560 A181561 A181562

KEYWORD

nonn,base

AUTHOR

Harvey P. Dale, Jan 29 2011

STATUS

approved

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Last modified September 28 21:27 EDT 2020. Contains 337393 sequences. (Running on oeis4.)