A144226 - OEIS

A144226

Prime numbers containing an equal number of odd and even digits.

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

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