login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A156345 Nonprimes with the same number of even digits and prime digits. 0

%I #8 Nov 21 2013 12:49:33

%S 0,1,9,10,12,20,21,22,34,36,38,45,54,56,58,63,65,74,76,78,85,87,90,91,

%T 92,99,100,102,110,111,112,119,120,121,122,129,134,136,138,143,145,

%U 147,154,156,158,165,174,176,178,183,185,187,190,192,200,201,202,209,210

%N Nonprimes with the same number of even digits and prime digits.

%C Even digits are 2, 4, 6 or 8. Prime digits are 2, 3, 5 or 7.

%e 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.

%t 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 *)

%Y Cf. A141468.

%K nonn,base,less

%O 1,3

%A _Juri-Stepan Gerasimov_, Feb 08 2009

%E Removed 69, inserted 99 and 209 . _R. J. Mathar_, Feb 13 2009

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 16 19:48 EDT 2024. Contains 371754 sequences. (Running on oeis4.)