A043688 a(n) = (s(n)-1)/2, where s(n) is the n-th number whose base-2 representation has exactly 5 runs.

10, 18, 20, 21, 22, 26, 34, 36, 37, 38, 40, 41, 43, 44, 45, 46, 50, 52, 53, 54, 58, 66, 68, 69, 70, 72, 73, 75, 76, 77, 78, 80, 81, 83, 87, 88, 89, 91, 92, 93, 94, 98, 100, 101, 102, 104, 105, 107, 108, 109, 110, 114, 116, 117, 118, 122

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Comments

a(n) = A238247(n) - 1. - Reinhard Zumkeller, Feb 20 2014

Links

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

Crossrefs

Cf. A238247.

Programs

Mathematica

(#-1)/2&/@Select[Range[400],Length[Split[IntegerDigits[#,2]]]==5&] (* Harvey P. Dale, Oct 04 2013 *)