%I A089045
%S A089045 1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,
               1,1,
%T A089045 0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,0,
               1,0,
%U A089045 1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,
               0
%V A089045 1,0,-1,-1,-1,0,1,0,-1,0,1,1,1,0,-1,-1,-1,0,1,1,1,0,-1,0,1,0,-1,-1,-1,
               0,1,0,-1,0,1,1,1,
%W A089045 0,-1,0,1,0,-1,-1,-1,0,1,1,1,0,-1,-1,-1,0,1,0,-1,0,1,1,1,0,-1,-1,-1,0,
               1,1,1,0,-1,0,1,0,
%X A089045 -1,-1,-1,0,1,1,1,0,-1,-1,-1,0,1,0,-1,0,1,1,1,0,-1,0,1,0,-1,-1,-1,0,1,
               0,-1,0,1,1,1,0
%N A089045 a(1)=1 and a(n)=a(n-1)+(-1)^floor(n/2)*a(floor(n/2)).
%F A089045 abs(a(n))=A035263(n)
%Y A089045 Cf. A001511, A035263.
%Y A089045 Sequence in context: A141260 A029883 A035263 this_sequence A070749 A059778 
               A104521
%Y A089045 Adjacent sequences: A089042 A089043 A089044 this_sequence A089046 A089047 
               A089048
%K A089045 sign
%O A089045 1,1
%A A089045 Benoit Cloitre (benoit7848c(AT)orange.fr), Dec 02 2003