%I #11 May 18 2019 07:14:00
%S 0,0,1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4,-3,-1,1,1,0,
%T 0,1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4,-3,-1,1,1,0,0,
%U 1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4,-3,-1,1,1,0,0,1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4
%N Expansion of -x^2*(x^4-2*x^3+x^2-2*x+1)*(x+1)^2 / ((x-1)*(x^8-x^4+1)).
%C It appears that (a(n)) has period 24.
%H Colin Barker, <a href="/A111914/b111914.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1,-1,0,0,-1,1).
%F a(n) = a(n-1) + a(n-4) - a(n-5) - a(n-8) + a(n-9) for n > 8. - _Colin Barker_, May 18 2019
%o 4jbasesigcycsumseq[ + .5'i + .5j' + .5'ij' + .5e], sumtype: Y[8] = (int)Y[6] - (int)Y[7] + Y[8] + sum (internal program code); apart from initial term 0.
%o (PARI) concat([0,0], Vec(x^2*(1 + x)^2*(1 - 2*x + x^2 - 2*x^3 + x^4) / ((1 - x)*(1 - x^4 + x^8)) + O(x^40))) \\ _Colin Barker_, May 18 2019
%Y Cf. A111912, A111913, A111915, A085846.
%K easy,sign
%O 0,6
%A _Creighton Dement_, Aug 20 2005
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