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A156345
Nonprimes with the same number of even digits and prime digits.
0
0, 1, 9, 10, 12, 20, 21, 22, 34, 36, 38, 45, 54, 56, 58, 63, 65, 74, 76, 78, 85, 87, 90, 91, 92, 99, 100, 102, 110, 111, 112, 119, 120, 121, 122, 129, 134, 136, 138, 143, 145, 147, 154, 156, 158, 165, 174, 176, 178, 183, 185, 187, 190, 192, 200, 201, 202, 209, 210
OFFSET
1,3
COMMENTS
Even digits are 2, 4, 6 or 8. Prime digits are 2, 3, 5 or 7.
EXAMPLE
0(number=0), 1(number=0), 9(number=0), 10(number=0), 12(number=1), 20(number=1), 21(number=1), 22(number=2), 34(number=1), etc.
MATHEMATICA
okQ[n_]:=Module[{idn=IntegerDigits[n]}, !PrimeQ[n] && Count[idn, _?PrimeQ] == Count[idn, _?EvenQ]-Count[idn, 0]]; Select[Range[0, 250], okQ] (* Harvey P. Dale, Jan 12 2012 *)
CROSSREFS
Cf. A141468.
Sequence in context: A158581 A343258 A078459 * A078390 A354038 A216780
KEYWORD
nonn,base,less
AUTHOR
EXTENSIONS
Removed 69, inserted 99 and 209 . R. J. Mathar, Feb 13 2009
STATUS
approved