A037014 Numbers n with property that reading binary expansion from right to left (from least significant to most significant), run lengths do not increase.

0, 1, 2, 3, 4, 5, 7, 8, 10, 11, 12, 15, 16, 19, 20, 21, 23, 24, 31, 32, 39, 40, 42, 43, 44, 47, 48, 51, 56, 63, 64, 71, 76, 79, 80, 83, 84, 85, 87, 88, 95, 96, 103, 112, 127, 128, 143, 152, 159, 160, 167, 168, 170, 171, 172, 175, 176, 179, 184, 191, 192, 199, 204, 207

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy
• base
• nice

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to binary expansion of n

Crossrefs

Cf. A037013 (subsequence), A037016, A037015.

Programs

Haskell

import Data.List (unfoldr, group)
a037014 n = a037014_list !! (n-1)
a037014_list = 0 : filter
   (all (<= 0) . (\x -> zipWith (-) (tail $ rls x) $ rls x)) [1..] where
       rls = map length . group . unfoldr
             (\x -> if x == 0 then Nothing else Just $ swap $ divMod x 2)
-- Reinhard Zumkeller, Mar 10 2012

Mathematica

Select[Range[0,250],Min[Differences[Length/@Split[IntegerDigits[ #,2]]]]>= 0&] (* Harvey P. Dale, Jan 30 2013 *)

Extensions

More terms from Patrick De Geest, Feb 15 1999

Offset fixed by Reinhard Zumkeller, Mar 10 2012