A190610 a(1)=a(2)=1; thereafter a(n) = a(ceiling(n/2))-a(floor(n/2)).

1, 1, 0, 0, -1, 0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, -1, 0, 1, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 1, 0, 1, 0, -1, 0, 1, 0, -1, 0, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 1, 0, 1, 0, -1, 0, 1, 0, -1, 0, -1, 0, 1, 0, 1, 0, -1, 0, -1, 0, 1, 0, -1, 0, 1, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0

Offset: 1

Author

N. J. A. Sloane, May 13 2011, based on a posting by Benoit CLOITRE to the Sequence Fans Mailing List, Apr 29 2011

Keywords

• sign

Crossrefs

Cf. A190608, A190609.

Programs

Maple

f:=proc(n) option remember; local r; r:=1;
if n <= 2 then 1 else r*(f(ceil(n/2))-f(floor(n/2))); fi; end;