A173024 - OEIS

%I #12 Apr 14 2023 10:54:06

%S 0,7,14,15,28,30,31,56,60,62,63,112,119,120,124,126,127,224,231,238,

%T 239,240,247,248,252,254,255,448,455,462,463,476,478,479,480,487,494,

%U 495,496,503,504,508,510,511,896,903,910,911,924,926,927,952,956,958,959

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

%C Intersection of A144795 and A173025.

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

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

%H Harvey P. Dale, <a href="/A173024/b173024.txt">Table of n, a(n) for n = 1..1000</a>

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

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

%Y Cf. A005251, A144795, A173021.

%K base,nonn

%O 1,2

%A _Reinhard Zumkeller_, Feb 07 2010