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%I #11 Sep 08 2022 08:45:08
%S 1,0,-1,-2,1,4,3,-6,-11,0,23,22,-23,-68,-21,114,157,-72,-385,-242,529,
%T 1012,-45,-2070,-1979,2160,6119,1798,-10439,-14036,6843,34914,21229,
%U -48600,-91057,6142,188257,175972,-200541,-552486,-151403,953568,1256375,-650762,-3163511,-1861988,4465035
%N Expansion of 1/(1+x^2+2*x^3).
%H G. C. Greubel, <a href="/A077963/b077963.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,-1,-2).
%F a(n) = (-1)^n * A077912(n). - _G. C. Greubel_, Jun 23 2019
%t CoefficientList[Series[1/(1+x^2+2*x^3), {x,0,50}], x] (* or *) LinearRecurrence[{0,-1,-2}, {1,0,-1}, 50] (* _G. C. Greubel_, Jun 23 2019 *)
%o (PARI) my(x='x+O('x^50)); Vec(1/(1+x^2+2*x^3)) \\ _G. C. Greubel_, Jun 23 2019
%o (Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!( 1/(1+x^2+2*x^3) )); // _G. C. Greubel_, Jun 23 2019
%o (Sage) (1/(1+x^2+2*x^3)).series(x, 50).coefficients(x, sparse=False) # _G. C. Greubel_, Jun 23 2019
%o (GAP) a:=[1,0,-1];; for n in [4..50] do a[n]:=-a[n-2]-2*a[n-3]; od; a; # _G. C. Greubel_, Jun 23 2019
%Y Cf. A077912.
%K sign,easy
%O 0,4
%A _N. J. A. Sloane_, Nov 17 2002
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