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A173024
Numbers having neither isolated ones nor isolated double ones in their binary representations.
4
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
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
KEYWORD
base,nonn
AUTHOR
Reinhard Zumkeller, Feb 07 2010
STATUS
approved