A153033 Numbers with adjacent 1's and no adjacent 0's in binary expansion.

3, 6, 7, 11, 13, 14, 15, 22, 23, 26, 27, 29, 30, 31, 43, 45, 46, 47, 53, 54, 55, 58, 59, 61, 62, 63, 86, 87, 90, 91, 93, 94, 95, 106, 107, 109, 110, 111, 117, 118, 119, 122, 123, 125, 126, 127, 171, 173, 174, 175, 181, 182, 183, 186, 187, 189, 190, 191, 213, 214, 215

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(1)=3 because bin(3)= 11.

Maple

filter:= proc(n) local L;
  L:= convert(n, base, 2);
  L:= L[1..-2]+L[2..-1];
  has(L, 2) and not has(L, 0)
end proc:
select(filter, [$3..300]); # Robert Israel, Jun 17 2020

Mathematica

fQ[n_] := Block[{st = Union@ Split@ IntegerDigits[n, 2]}, MemberQ[st, {1, __}] && !MemberQ[st, {0, __}]]; Select[Range@218, fQ@# &] (* Robert G. Wilson v, Dec 21 2008 *)
Select[Range[300], SequenceCount[IntegerDigits[#, 2], {0, 0}]== 0 && SequenceCount[ IntegerDigits[#, 2], {1, 1}]>0&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 11 2017 *)

Crossrefs

Sequence in context: A306718 A022550 A237883 * A353240 A282167 A076644

Adjacent sequences: A153030 A153031 A153032 * A153034 A153035 A153036

Keyword

base,easy,nonn

Author

Gil Broussard, Dec 17 2008

Extensions

Extended by Robert G. Wilson v, Dec 21 2008

Status

approved