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%I #10 Sep 08 2022 08:45:08
%S 1,-1,2,0,2,4,4,12,16,32,56,96,176,304,544,960,1696,3008,5312,9408,
%T 16640,29440,52096,92160,163072,288512,510464,903168,1597952,2827264,
%U 5002240,8850432,15659008,27705344,49018880,86728704,153448448,271495168,480354304
%N Expansion of (1-x)/(1-2*x^2-2*x^3).
%H G. C. Greubel, <a href="/A078023/b078023.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (0,2,2).
%t CoefficientList[Series[(1-x)/(1-2*x^2-2*x^3), {x,0,40}], x] (* _G. C. Greubel_, Aug 04 2019 *)
%o (PARI) my(x='x+O('x^40)); Vec((1-x)/(1-2*x^2-2*x^3)) \\ _G. C. Greubel_, Aug 04 2019
%o (Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1-x)/(1-2*x^2-2*x^3) )); // _G. C. Greubel_, Aug 04 2019
%o (Sage) ((1-x)/(1-2*x^2-2*x^3)).series(x, 40).coefficients(x, sparse=False) # _G. C. Greubel_, Aug 04 2019
%o (GAP) a:=[1,-1,2];; for n in [4..40] do a[n]:=2*a[n-2]+2*a[n-3]; od; a; # _G. C. Greubel_, Aug 04 2019
%K sign
%O 0,3
%A _N. J. A. Sloane_, Nov 17 2002