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A179039
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Emirps with a single 7 as the only prime digit.
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1
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17, 71, 79, 97, 107, 167, 179, 701, 709, 761, 769, 907, 967, 971, 1097, 1471, 1487, 1741, 1789, 1847, 1867, 1879, 1979, 7481, 7649, 7681, 7699, 7841, 7901, 7949, 9467, 9479, 9497, 9679, 9749, 9769, 9781, 9791, 9871, 9967, 10007, 10067, 10079, 10487
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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emirpQ[n_] := Module[{idn=IntegerDigits[n], ridn}, ridn=Reverse[idn]; idn != ridn && PrimeQ[FromDigits[ridn]]]; only7Q[n_] := DigitCount[n, 10, 7] == 1 && Total[DigitCount[n, 10, {2, 3, 5}]] == 0; Select[Select[Prime[Range[1500]], emirpQ], only7Q] (* Harvey P. Dale, Jan 06 2011 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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Definition clarified by Harvey P. Dale, Jan 06 2011
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STATUS
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approved
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