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A043689 a(n) = (s(n)-1)/2, where s(n) is the n-th number whose base-2 representation has exactly 7 runs. 2
42, 74, 82, 84, 85, 86, 90, 106, 138, 146, 148, 149, 150, 154, 162, 164, 165, 166, 168, 169, 171, 172, 173, 174, 178, 180, 181, 182, 186, 202, 210, 212, 213, 214, 218, 234, 266, 274, 276, 277, 278, 282, 290, 292, 293, 294, 296 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = A238248(n) - 1. - Reinhard Zumkeller, Feb 20 2014

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

(# - 1)/2&/@Select[Range[50], Length[Split[IntegerDigits[#, 2]]]==7&] (* Vincenzo Librandi, Feb 22 2014 *)

CROSSREFS

Cf. A238248.

Sequence in context: A305153 A340570 A261621 * A043573 A043733 A043745

Adjacent sequences:  A043686 A043687 A043688 * A043690 A043691 A043692

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified September 26 06:16 EDT 2021. Contains 347664 sequences. (Running on oeis4.)