A043722 - OEIS

%I #14 Oct 04 2023 05:16:59

%S 1,3,7,10,15,18,20,22,26,31,34,36,38,40,44,46,50,52,54,58,63,66,68,70,

%T 72,76,78,80,85,88,92,94,98,100,102,104,108,110,114,116,118,122,127,

%U 130,132,134,136,140,142,144,149,152,156,158

%N Numbers whose number of runs in the base-2 representation is congruent to 1 mod 3.

%H Harvey P. Dale, <a href="/A043722/b043722.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[200],Mod[Length[Split[IntegerDigits[#,2]]],3]==1&] (* _Harvey P. Dale_, Mar 24 2022 *)

%o (PARI) isok(k) = (hammingweight(bitxor(k, k>>1)) % 3) == 1; \\ _Michel Marcus_, Oct 04 2023

%Y Cf. A005811.

%K nonn,base

%O 1,2

%A _Clark Kimberling_