|
%I #13 Jan 22 2017 21:57:37
%S 1,3,-9,-81,-243,-1215,-5103,-15309,-59049,-216513,-649539,-2302911,
%T -7971615,-23914845,-81310473,-272629233,-817887699,-2711943423,
%U -8910671247,-26732013741,-87169610025,-282429536481,-847288609443
%N a(n) = 3^n*A168053(n).
%C Hankel transform of A171556.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3,0,27,-81).
%F G.f.: (1-18*x^2-81*x^3)/((1-3*x)^2*(1+3*x+9*x^2)).
%t CoefficientList[Series[(1 - 18 x^2 - 81 x^3)/((1 - 3 x)^2*(1 + 3 x + 9 x^2)), {x, 0, 30}], x] (* _Wesley Ivan Hurt_, Jan 21 2017 *)
%o (PARI) Vec((1-18*x^2-81*x^3)/((1-3*x)^2*(1+3*x+9*x^2)) + O(x^30)) \\ _Michel Marcus_, Feb 10 2015
%Y Cf. A168053, A171556.
%K easy,sign
%O 0,2
%A _Paul Barry_, Dec 11 2009
|
