A044904 Numbers whose base-3 run lengths alternate: odd, even, odd, ...

1, 2, 9, 13, 17, 18, 22, 26, 28, 29, 51, 52, 55, 56, 66, 68, 81, 117, 121, 125, 161, 162, 202, 234, 238, 242, 244, 245, 252, 256, 260, 261, 265, 269, 352, 353, 375, 376, 459, 463, 467, 468, 472, 476, 483, 484, 487, 488, 495, 499

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

b3rQ[n_]:=Module[{r=Boole[OddQ/@(Length/@Split[IntegerDigits[ n, 3]])]}, r == PadRight[{}, Length[r], {1, 0}]]; Select[Range[500], b3rQ] (* Harvey P. Dale, Jul 17 2020 *)

Crossrefs

Cf. A007089.

Sequence in context: A171234 A287069 A068047 * A234902 A138946 A037385

Adjacent sequences: A044901 A044902 A044903 * A044905 A044906 A044907

Keyword

nonn,base

Author

Clark Kimberling

Status

approved