A045016 - OEIS

%I #12 May 28 2023 22:19:17

%S 21,86,87,89,93,101,117,149,213,346,347,350,351,358,359,361,365,374,

%T 375,377,381,406,407,409,413,421,437,470,471,473,477,485,501,598,599,

%U 601,605,613,629,661,725,854,855,857,861,869,885

%N Numbers whose base-4 representation contains no 0's and exactly three 1's.

%H Vincenzo Librandi, <a href="/A045016/b045016.txt">Table of n, a(n) for n = 1..3500</a>

%t Select[Range[10000], DigitCount[#, 4, 0] == 0 && DigitCount[#, 4, 1] == 3 &] (* _Vincenzo Librandi_, Sep 21 2016 *)

%Y Cf. A007090.

%K nonn,base

%O 1,1

%A _Clark Kimberling_