A031469 - OEIS

%I #11 Oct 01 2021 18:32:31

%S 255,511,767,895,959,991,1007,1015,1019,1021,1022,1535,1791,1919,1983,

%T 2015,2031,2039,2043,2045,2046,2559,2815,2943,3007,3039,3055,3063,

%U 3067,3069,3070,3327,3455,3519,3551,3567,3575,3579,3581,3582

%N Numbers whose base-4 representation has 4 fewer 0's than 3's.

%t Select[Range@4000,(s=#;Differences[Count[IntegerDigits[s,4],#]&/@{0,3}]=={4})&] (* _Giorgos Kalogeropoulos_, Jul 04 2021 *)

%t Select[Range[3600],DigitCount[#,4,0]==DigitCount[#,4,3]-4&] (* _Harvey P. Dale_, Oct 01 2021 *)

%Y Cf. A007090.

%K nonn,base

%O 1,1

%A _Clark Kimberling_