|
%I #9 Apr 08 2017 09:50:08
%S 1,1,1,0,1,1,0,0,1,1,0,0,1,0,0,1,1,0,0,0,0,1,1,0,0,1,0,-1,1,1,0,0,1,0,
%T 0,1,0,0,0,0,0,1,1,0,1,0,-1,0,1,0,0,1,0,0,1,0,0,1,0,-1,1,1,-1,0,1,0,0,
%U 1,0,0,1,0,0,1,0,-1,0,0,0,1,1,0,1,0,-1,1,1,-1,0,1,-1,0,2,0,-1,1,0,-1,1,1,0,1,0,-1,1
%N Expansion of Product_{k>0} (1-x^(3k))/(1-x^(3k-2)).
%C |a(n)|<2 if n<92, |a(n)|<3 if n<204.
%H Seiichi Manyama, <a href="/A113706/b113706.txt">Table of n, a(n) for n = 0..10000</a>
%F Euler transform of period 3 sequence [1, 0, -1, ...].
%F G.f.: Product_{k>0} (1-x^(3k))/(1-x^(3k-2)).
%o (PARI) {a(n)=if(n<0, 0, polcoeff( prod(k=1,n,(1-x^k)^([1,-1,0][k%3+1]),1+x*O(x^n)), n))}
%Y Cf. A143240.
%K sign
%O 0,93
%A _Michael Somos_, Nov 06 2005
|
