A160531 Those positive integers n that contain both odd-lengthed and even-lengthed runs of 0's and 1's when n is represented in binary.

4, 6, 9, 11, 13, 16, 18, 19, 20, 22, 24, 25, 26, 27, 28, 30, 33, 35, 36, 37, 38, 39, 41, 43, 44, 45, 47, 49, 50, 52, 53, 54, 55, 57, 59, 61, 64, 66, 67, 68, 70, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 83, 84, 86, 88, 89, 90, 91, 92, 94, 96, 97, 98, 99, 100, 101, 102, 103, 104

Offset

1,1

Comments

Let the binary representation of n be thought of as a string of 0's and 1's. By a "run" of 0's or 1's, it is meant either a contiguous substring all of 0's bounded by 1's or the by the edge of the string, or a contiguous substring all of 1's bounded by 0's or the by the edge of the string.

This sequence contains precisely those positive integers that are in neither sequence A001196 nor sequence A160530.

Links

Table of n, a(n) for n=1..69.

Mathematica

Select[Range[120], Select[l=Length/@Split[IntegerDigits[ #, 2]], EvenQ]!={}&&Select[l, OddQ]!={}&] (* Ray Chandler, May 19 2009 *)

Crossrefs

A001196, A160530

Sequence in context: A258979 A258026 A246779 * A190348 A189363 A189926

Adjacent sequences: A160528 A160529 A160530 * A160532 A160533 A160534

Keyword

base,nonn

Author

Leroy Quet, May 17 2009

Extensions

Extended by Ray Chandler, May 19 2009

Status

approved