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A077992 Expansion of 1/(1+2*x+2*x^2-x^3). 1

%I

%S 1,-2,2,1,-8,16,-15,-10,66,-127,112,96,-543,1006,-830,-895,4456,-7952,

%T 6097,8166,-36478,62721,-44320,-73280,297921,-493602,318082,648961,

%U -2427688,3875536,-2246735,-5685290,19739586,-30355327,15546192,49357856,-160163423,237157326,-104629950

%N Expansion of 1/(1+2*x+2*x^2-x^3).

%H G. C. Greubel, <a href="/A077992/b077992.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 (-2,-2,1).

%F a(n) = (-1)^n*A077944(n).

%t CoefficientList[Series[1/(1+2x+2x^2-x^3),{x,0,40}],x] (* or *) LinearRecurrence[ {-2,-2,1},{1,-2,2},40] (* _Harvey P. Dale_, Aug 17 2017 *)

%o (PARI) my(x='x+O('x^40)); Vec(1/(1+2*x+2*x^2-x^3)) \\ _G. C. Greubel_, Jun 26 2019

%o (MAGMA) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( 1/(1+2*x+2*x^2-x^3) )); // _G. C. Greubel_, Jun 26 2019

%o (Sage) (1/(1+2*x+2*x^2-x^3)).series(x, 40).coefficients(x, sparse=False) # _G. C. Greubel_, Jun 26 2019

%o (GAP) a:=[1,-2,2];; for n in [4..40] do a[n]:=-2*a[n-1]-2*a[n-2]+a[n-3]; od; a; # _G. C. Greubel_, Jun 26 2019

%Y Cf. A077944.

%K sign

%O 0,2

%A _N. J. A. Sloane_, Nov 17 2002

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Last modified July 13 17:54 EDT 2020. Contains 335689 sequences. (Running on oeis4.)