%I A059448
%S A059448 0,1,0,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,
%T A059448 0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
%U A059448 1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,0,1
%N A059448 If A_k are the terms from 2^(k-1) through to 2^k-1, then A_(k+1) is B_k 
               A_k where B_k is A_k with 0's and 1's swapped, starting from a(1)=0; 
               also parity of number of zero digits when n is written in binary.
%C A059448 a(0) not given as it could be 1 or 0 depending on the definition or formula 
               used.
%H A059448 <a href="Sindx_Ch.html#char_fns">Index entries for characteristic functions</
               a>
%F A059448 a(2n)=1-a(n); a(2n+1)=a(n)=1-a(2n). If 2^k<=n<2^(k+1) then a(n)=1-a(n-2^(k-1)). 
               a(n)=A023416(n) mod 2 =A059009(n)-2n =2n+1-A059010(n) =|A010060(n)-A030300(n-1)|.
%F A059448 Let b(1)=1 and b(n)=b(n-ceil(n/2))-b(n-floor(n/2)) then for n>=1 a(n)=(1/
               2)*(1-b(2n+1)) - Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 26 
               2005
%Y A059448 Characteristic function of A059009.
%Y A059448 Sequence in context: A080846 A082401 A157238 this_sequence A156259 A038219 
               A138710
%Y A059448 Adjacent sequences: A059445 A059446 A059447 this_sequence A059449 A059450 
               A059451
%K A059448 nice,nonn
%O A059448 1,1
%A A059448 Henry Bottomley (se16(AT)btinternet.com), Feb 02 2001