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

Author

Reinhard Zumkeller, Feb 07 2010

Keywords

• base
• nonn

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

Crossrefs

Cf. A005251, A144795, A173021.

Programs

Mathematica

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

Formula

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