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%I #11 Oct 14 2014 08:26:25
%S 1,1,1,0,-1,-1,0,2,2,0,-1,-1,0,3,3,0,-2,-2,0,5,5,0,-3,-3,0,8,8,0,-5,
%T -5,0,13,13,0,-8,-8,0,21,21,0,-13,-13,0,34,34,0,-21,-21,0,55,55,0,-34,
%U -34,0,89,89,0,-55,-55,0,144,144,0,-89,-89,0,233,233,0,-144,-144,0,377,377,0,-233,-233,0,610,610,0,-377,-377,0,987
%N Let u(1)=u(2)=u(3)=1, u(n)=sign(u(n-1)-u(n-2))/(u(n-3)+1); then a(n) is the numerator of u(n).
%F F(k) denotes the k-th Fibonacci number: a(6k)=-F(k); a(6k+1)=0; a(6k+2)=a(6k+3)=F(k+2); a(6k+4)=0; a(6k+5)=-F(k+1).
%F Empirical g.f.: x*(x^12-x^8-x^7+x^6+x^5+x^4-x^2-x-1) / (x^12+x^6-1). - _Colin Barker_, Oct 14 2014
%Y Cf. A076899 (denominators).
%K frac,sign
%O 1,8
%A _Benoit Cloitre_, Nov 26 2002
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