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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.
1
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.
MATHEMATICA
Select[Range[120], Select[l=Length/@Split[IntegerDigits[ #, 2]], EvenQ]!={}&&Select[l, OddQ]!={}&] (* Ray Chandler, May 19 2009 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Leroy Quet, May 17 2009
EXTENSIONS
Extended by Ray Chandler, May 19 2009
STATUS
approved