A043725 Numbers whose number of runs in the base-2 representation is congruent to 1 mod 4.

1, 3, 7, 15, 21, 31, 37, 41, 43, 45, 53, 63, 69, 73, 75, 77, 81, 83, 87, 89, 91, 93, 101, 105, 107, 109, 117, 127, 133, 137, 139, 141, 145, 147, 151, 153, 155, 157, 161, 163, 167, 175, 177, 179, 183, 185, 187, 189, 197, 201, 203, 205

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Paul Barry, Conjectures and results on some generalized Rueppel sequences, arXiv:2107.00442 [math.CO], 2021.

Programs

Mathematica

Select[Range[250],Mod[Length[Split[IntegerDigits[#,2]]],4]==1&] (* Harvey P. Dale, Dec 10 2018 *)