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A144226
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Prime numbers containing an equal number of odd and even digits.
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6
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23, 29, 41, 43, 47, 61, 67, 83, 89, 1009, 1021, 1049, 1061, 1063, 1069, 1087, 1201, 1223, 1229, 1249, 1283, 1289, 1409, 1423, 1427, 1429, 1447, 1481, 1483, 1487, 1489, 1601, 1607, 1609, 1621, 1627, 1663, 1667, 1669, 1801, 1823, 1847, 1861, 1867, 1889
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OFFSET
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1,1
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COMMENTS
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Can it be proved that this sequence has relative density 0 in the primes? Numbers with equal numbers of even and odd decimal digits have k * n/sqrt(log(n)) members up to n (k varies by upper or lower density). - Charles R Greathouse IV, Nov 12 2010
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LINKS
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FORMULA
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EXAMPLE
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The prime 1889 contains an equal number of odd and even digits.
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MATHEMATICA
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fQ[n_] := Block[{id = IntegerDigits[n]}, Length[Select[id, OddQ]] == Length[Select[id, EvenQ]]]; Select[Prime[Range[300]], fQ] (* Robert G. Wilson v, Sep 24 2008 *)
eoQ[n_]:=Module[{idn=IntegerDigits[n]}, Count[idn, _?OddQ]==Count[ idn, _?EvenQ]]; Select[Prime[Range[300]], eoQ] (* Harvey P. Dale, Mar 07 2017 *)
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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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