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%I #14 Jan 13 2020 11:03:36
%S 1,18,224,2832,35776,451968,5709824,72133632,911282176,11512455168,
%T 145439719424,1837376274432,23212033048576,293243406778368,
%U 3704617145729024,46801353002975232,591253173201534976,7469448902442221568,94363412214918938624,1192116537798565036032
%N Expansion of (1+6*x)/(1-12*x-8*x^2).
%H Tomislav Došlić and Frode Måløy, <a href="http://dx.doi.org/10.1016/j.disc.2009.11.026">Chain hexagonal cacti: Matchings and independent sets</a>, Discr. Math., 310 (2010), 1676-1690.
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (12,8).
%t CoefficientList[Series[(1+6x)/(1-12x-8x^2),{x,0,20}],x] (* or *) LinearRecurrence[ {12,8},{1,18},20]
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, May 22 2010