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 A144226 Prime numbers containing an equal number of odd and even digits. 6
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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 LINKS T. D. Noe, Table of n, a(n) for n = 1..10000 FORMULA A000040 INTERSECTION A227870. - Jonathan Vos Post, Nov 04 2013 EXAMPLE The prime 1889 contains an equal number of odd and even digits. MATHEMATICA 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 *) CROSSREFS Cf. A000040, A144205, A227870. Sequence in context: A156983 A230456 A174196 * A173709 A225319 A228139 Adjacent sequences:  A144223 A144224 A144225 * A144227 A144228 A144229 KEYWORD nonn,base AUTHOR Parthasarathy Nambi, Sep 15 2008 STATUS approved

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Last modified February 21 04:18 EST 2019. Contains 320371 sequences. (Running on oeis4.)