A043593 - OEIS

%I #9 Apr 25 2021 01:26:12

%S 4,6,7,8,9,11,12,13,14,16,20,22,23,26,31,32,37,40,41,43,47,48,53,58,

%T 60,61,62,64,80,84,86,87,90,95,106,127,128,149,160,165,168,169,171,

%U 175,191,192,213,234,240,245,250,252,253,254,256

%N Numbers whose base-4 representation has exactly 2 runs.

%Y Cf. A007090.

%K nonn,base

%O 1,1

%A _Clark Kimberling_