The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A175021 A positive integer n is included if n is not the smallest positive integer with its particular multiset of run-lengths (of either 0 or 1 considered together) in its binary representation. 2

%I #10 Sep 03 2017 21:30:35

%S 6,11,13,14,20,22,23,25,26,27,28,29,30,38,39,40,41,43,44,45,46,47,49,

%T 50,52,53,54,55,57,58,59,60,61,62,70,72,75,77,78,79,80,81,82,83,84,86,

%U 87,88,89,90,91,92,93,94,95,97,98,100,101,102,103,104,105,106,107,108,109

%N A positive integer n is included if n is not the smallest positive integer with its particular multiset of run-lengths (of either 0 or 1 considered together) in its binary representation.

%C A175020 contains those positive integers not in this sequence.

%H Michael De Vlieger, <a href="/A175021/b175021.txt">Table of n, a(n) for n = 1..10000</a>

%e 9 in binary is 1001. The run lengths form the multiset (1,2,1). Since no positive integer < 9 has this same multiset of run lengths, then 9 is not in this sequence. On the other hand, 23 in binary is 10111. The run-lengths are (1,1,3). But 17 (which is < 23) in binary is 10001, which has the run-lengths of (1,3,1). Since the multisets (1,1,3) and (1,3,1) are identical, then 23 is in this sequence.

%t Block[{nn = 109, s}, s = Array[Sort@ Map[Length, Split@ IntegerDigits[#, 2]] &, nn]; Complement[Range[nn], Values[PositionIndex@ s][[All, 1]] ]] (* _Michael De Vlieger_, Sep 03 2017 *)

%Y Cf. A175020.

%K base,nonn

%O 1,1

%A _Leroy Quet_, Nov 03 2009

%E Extended by _Ray Chandler_, Mar 11 2010

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 14 14:06 EDT 2024. Contains 372533 sequences. (Running on oeis4.)