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A175416 Those positive integers n that when written in binary, each run of 0's and 1's has a length which is coprime to the number of binary digits of n. 2
1, 2, 4, 5, 6, 8, 10, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 42, 62, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..5000

EXAMPLE

70 in binary is 1000110. There is a run of one 1, followed by a run of three 0's, followed by a run of two 1's, followed finally by a run of one 0. And there are seven binary digits all together. Since 1, 3, 2, and 1 each are coprime to 7, then 70 is in the sequence.

MATHEMATICA

cpQ[n_]:=Module[{d=Length/@Split[IntegerDigits[n, 2]]}, And@@CoprimeQ[ d, Total[ d]]]; Select[Range[100], cpQ] (* Harvey P. Dale, Mar 25 2013 *)

CROSSREFS

Cf. A175415

Sequence in context: A020640 A068383 A276603 * A190854 A069872 A216163

Adjacent sequences:  A175413 A175414 A175415 * A175417 A175418 A175419

KEYWORD

base,nonn

AUTHOR

Leroy Quet, May 07 2010

EXTENSIONS

More terms from Sean A. Irvine, Mar 02 2011

STATUS

approved

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Last modified March 20 05:29 EDT 2019. Contains 321344 sequences. (Running on oeis4.)