A085556 Numbers that have exactly as many prime digits as nonprime digits.

12, 13, 15, 17, 20, 21, 24, 26, 28, 29, 30, 31, 34, 36, 38, 39, 42, 43, 45, 47, 50, 51, 54, 56, 58, 59, 62, 63, 65, 67, 70, 71, 74, 76, 78, 79, 82, 83, 85, 87, 92, 93, 95, 97, 1022, 1023, 1025, 1027, 1032, 1033, 1035, 1037, 1052, 1053, 1055, 1057, 1072, 1073, 1075

Offset: 1

Author

Jason Earls, Jul 04 2003

Keywords

• base
• easy
• nonn

Crossrefs

Cf. A085520.

Programs

Mathematica

Select[Range[1200],Count[IntegerDigits[#],?PrimeQ]== IntegerLength[#]/2&] (* _Harvey P. Dale, Jun 02 2011 *)