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A163562
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Composite numbers such that exactly ten distinct permutations of digits are prime.
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4
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1079, 1790, 1795, 1798, 1897, 1957, 1970, 1975, 1978, 5719, 5917, 5971, 7091, 7189, 7190, 7195, 7198, 7519, 7819, 7891, 7910, 7915, 7918, 7981, 8197, 8791, 8917, 9017, 9071, 9107, 9170, 9175, 9178, 9517, 9571, 9701, 9710, 9715, 9718, 9751, 10019
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(1) = 1079 because 1079 is composite, the ten permutations 179, 197, 719, 971, 1097, 1709, 1907, 7019, 7109, and 7901 are all prime, and no other permutation of 1079 is prime.
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MATHEMATICA
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Select[Range[11000], CompositeQ[#]&&Count[FromDigits/@Permutations[IntegerDigits[#]], _?PrimeQ] ==10&] (* Harvey P. Dale, Jun 03 2023 *)
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CROSSREFS
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KEYWORD
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easy,nonn,base
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AUTHOR
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STATUS
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approved
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