%I A128834
%S A128834 0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,
%T A128834 1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,
%U A128834 1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1
%V A128834 0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,
               0,1,1,0,-1,-1,0,
%W A128834 1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,
               1,1,0,-1,-1,0,1,
%X A128834 1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,1,0,-1,-1,0,1,
               1
%N A128834 Periodic sequence 0,1,1,0,-1,-1,...
%C A128834 Unsigned version in A011655 .
%F A128834 a(0)=0, a(1)=1,a(n+1)=a(n)-a(n-1) for n>=1 . G.f.:x*(1+x)/(1+x^3) .
%F A128834 Euler transform of length 6 sequence [ 1, -1, -1, 0, 0, 1]. - Michael 
               Somos Apr 15 2007
%F A128834 G.f. A(x) satisfies 0= f(A(x), A(x^2)) where f(u, v)= v -u^2 +2*u*v -2*u^2*v 
               . - Michael Somos Apr 15 2007
%F A128834 G.f. A(x) satisfies 0= f(A(x), A(x^3)) where f(u, v)= v -u^3 +3*u*v -3*u^3*v 
               . - Michael Somos Apr 15 2007
%F A128834 a(n)=(1/6)*{-(n mod 6)+[(n+2) mod 6]+[(n+3) mod 6]-[(n+5) mod 6]}, with 
               n>=0 - Paolo P. Lava (ppl(AT)spl.at), Jun 11 2007
%F A128834 a(n) = A010892(n-1) . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Feb 08 2008
%F A128834 a(n) is multiplicative with a(3^e) = 0^e, a(p^e) = 1 if p == 1 (mod 3), 
               a(p^e) = (-1)^e if p == 2 (mod 3) . - Michael Somos Apr 15 2007
%F A128834 a(n)=2sin(n*pi/3)/sqrt(3) [From Jaume Oliver Lafont (joliverlafont(AT)gmail.com), 
               Dec 05 2008]
%e A128834 x + x^2 - x^4 - x^5 + x^7 + x^8 - x^10 - x^11 + x^13 + x^14 - x^16 + 
               ...
%o A128834 (PARI) {a(n)= [0, 1, 1, 0, -1, -1][n%6 +1]}
%Y A128834 a(n)=A010892(n+5) [From Jaume Oliver Lafont (joliverlafont(AT)gmail.com), 
               Dec 05 2008]
%Y A128834 Sequence in context: A092220 A011655 A102283 this_sequence A022928 A000494 
               A022933
%Y A128834 Adjacent sequences: A128831 A128832 A128833 this_sequence A128835 A128836 
               A128837
%K A128834 sign,mult
%O A128834 0,1
%A A128834 Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Apr 13 2007