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%I #18 Jan 02 2023 12:30:48
%S 1,2,7,15,47,106,312,731,2068,4983,13727,33757,91302,227846,608389,
%T 1534290,4059911,10315771,27122487,69284630,181339756,465000279,
%U 1213137668,3119218927,8119123683,20916102989,54354854050,140218109898,363965563145,939827989330,2437520805303,6298491488951,16326135100447
%N G.f.: (1-2*x^2)/(1-2*x-5*x^2+9*x^3).
%H Vincenzo Librandi, <a href="/A200862/b200862.txt">Table of n, a(n) for n = 0..1000</a>
%H Peter Lawrence et al., <a href="http://list.seqfan.eu/oldermail/seqfan/2011-November/008535.html">sequence challenge</a> and follow-up messages on the SeqFan list, Nov 21 2011
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,5,-9).
%F a(n) = 2*a(n-1) +5*a(n-2) -9*a(n-3) for n>2. - _Vincenzo Librandi_, Jun 30 2014
%t LinearRecurrence[{2,5,-9},{1,2,7},40] (* _Harvey P. Dale_, Jun 29 2014 *)
%t CoefficientList[Series[(1 - 2 x^2)/(1 - 2 x - 5 x^2 + 9 x^3), {x, 0, 40}], x] (* _Vincenzo Librandi_, Jun 30 2014 *)
%K nonn
%O 0,2
%A _N. J. A. Sloane_, Nov 23 2011
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