A039320 - OEIS

%I #14 Jun 29 2021 02:18:27

%S 18,30,67,79,102,109,123,126,127,129,131,132,137,144,165,177,198,205,

%T 210,211,213,215,216,219,233,240,263,275,312,324,361,373,410,422,445,

%U 452,466,469,470,472,474,475,480,487,508,520,541,548,553,554,556,558

%N Numbers whose base-7 representation has the same nonzero number of 2's and 4's.

%t Select[Range[600],DigitCount[#,7,2]==DigitCount[#,7,4]>0&] (* _Harvey P. Dale_, Nov 20 2016 *)

%Y Cf. A007093.

%K nonn,base,easy

%O 1,1

%A _Olivier Gérard_