%I #10 Oct 02 2023 11:23:10
%S 1,-2,5,-12,30,-73,180,-444,1095,-2699,6653,-16399,40421,-99632,
%T 245580,-605324,1492048,-3677712,9065100,-22344336,55075988,
%U -135755408,334620068,-824796535,2033020102,-5011139791,12351831632,-30445717146
%N Expansion of 1/(-x^11 + x^10 + 2*x^7 - x^6 - x^5 - x^4 - x^2 + 2*x + 1).
%D J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. xxxiii.
%H <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (-2, 1, 0, 1, 1, 1, -2, 0, 0, -1, 1).
%F G.f.: 1/(-x^11 + x^10 + 2*x^7 - x^6 - x^5 - x^4 - x^2 + 2*x + 1).
%t f[x_] = -1 + x + 2*x^4 - x^5 - x^6 - x^7 - x^9 + 2*x^10 + x^11;
%t g[x] = ExpandAll[x^11*f[1/x]];
%t a = Table[SeriesCoefficient[ Series[1/g[x], {x, 0, 50}], n], {n, 0, 50}]
%K sign,easy
%O 0,2
%A _Roger L. Bagula_, Mar 05 2009
%E New name from _Joerg Arndt_, Mar 20 2013