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A108632
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Semiprimes with prime digits (only digits 2,3,5,7 in semiprimes).
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4
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22, 25, 33, 35, 55, 57, 77, 235, 237, 253, 323, 327, 335, 355, 377, 527, 533, 535, 537, 553, 573, 723, 737, 753, 755, 2227, 2253, 2257, 2323, 2327, 2335, 2353, 2533, 2537, 2573, 2577, 2722, 2723, 2733, 2735, 2757, 2773, 3223, 3227, 3233, 3235, 3273, 3277
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OFFSET
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1,1
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COMMENTS
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Complement of 108631 in the class of semiprimes.
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LINKS
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MATHEMATICA
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fQ[n_]:=Plus@@Last/@FactorInteger[n]==2&&Union[{2, 3, 5, 7}, IntegerDigits[n]]=={2, 3, 5, 7}; Select[Range[4000], fQ[ # ]&]
Select[FromDigits/@Flatten[Table[Tuples[{2, 3, 5, 7}, n], {n, 2, 4}], 1], PrimeOmega[#]==2&] (* Harvey P. Dale, Oct 19 2012 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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