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%I #8 Mar 30 2012 16:52:02
%S 1,1,0,0,-2,0,0,0,-4,0,4,0,0,0,0,0,-8,0,8,0,8,0,-8,0,0,0,0,0,0,0,0,0,
%T -16,0,16,0,16,0,-16,0,16,0,-16,0,-16,0,16,0,0,0,0,0,0,0,0,0,0,0,0,0,
%U 0,0,0,0,-32,0,32,0,32,0,-32,0,32,0,-32,0,-32,0,32,0,32,0,-32,0,-32,0,32,0,-32,0,32,0,32
%N a(1)=a(2)=1; thereafter a(n) = 2*(a(ceiling(n/2))-a(floor(n/2))).
%p f:=proc(n) option remember; local r; r:=2;
%p if n <= 2 then 1 else r*(f(ceil(n/2))-f(floor(n/2))); fi; end;
%Y Cf. A190609, A190610.
%K sign
%O 1,5
%A _N. J. A. Sloane_, May 13 2011, based on a posting by Benoit CLOITRE to the Sequence Fans Mailing List, Apr 29 2011
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