A173024 Numbers having neither isolated ones nor isolated double ones in their binary representations.

0, 7, 14, 15, 28, 30, 31, 56, 60, 62, 63, 112, 119, 120, 124, 126, 127, 224, 231, 238, 239, 240, 247, 248, 252, 254, 255, 448, 455, 462, 463, 476, 478, 479, 480, 487, 494, 495, 496, 503, 504, 508, 510, 511, 896, 903, 910, 911, 924, 926, 927, 952, 956, 958, 959

Offset

1,2

Comments

Intersection of A144795 and A173025.

If m is a term then 2*m is also a term.

If m is an odd term then 2*m+1 is also a term.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

A173021(a(n+1)) = A173021(a(n)) + 1.

Mathematica

nioQ[n_]:=Min[Length/@Select[Split[IntegerDigits[n, 2]], FreeQ[#, 0]&]]>2; Select[ Range[ 0, 1000], nioQ] (* Harvey P. Dale, Jan 12 2023 *)

Crossrefs

Cf. A005251, A144795, A173021.

Sequence in context: A004759 A364287 A062056 * A115770 A086779 A269173

Adjacent sequences: A173021 A173022 A173023 * A173025 A173026 A173027

Keyword

base,nonn

Author

Reinhard Zumkeller, Feb 07 2010

Status

approved