%I
%S 0,1,1,1,1,1,1,0,1,1,1,0,1,0,0,0,1,1,1,0,1,0,0,0,1,0,0,0,0,0,0,0,1,1,
%T 1,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,
%U 1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0
%N 1 if binary weight of n is 1 or 2, otherwise 0.
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F For n>0: a(n) = 0^floor(A000120(n)/3).  _Reinhard Zumkeller_, Apr 07 2003
%t Table[If[MemberQ[{1,2},Total[IntegerDigits[n,2]]],1,0],{n,0,120}] (* _Harvey P. Dale_, Jul 26 2017 *)
%Y 1 if n is in A048645, 0 otherwise.
%K nonn
%O 0,1
%A _Benoit Cloitre_, Mar 29 2003
