%I #19 Apr 06 2024 05:43:51
%S 8,8,72,72,648,648,5832,5832,52488,52488,472392,472392,4251528,
%T 4251528,38263752,38263752,344373768,344373768,3099363912,3099363912,
%U 27894275208,27894275208,251048476872,251048476872,2259436291848,2259436291848,20334926626632
%N Number of palindromes of length n (in base 9).
%H Harvey P. Dale, <a href="/A117861/b117861.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,9).
%F a(n) = 8*9^floor((n-1)/2).
%F G.f.: 8*x*(1+x)/(1-9*x^2). a(n) = 8*3^(n-2)*(2-(-1)^n). - _Bruno Berselli_, Oct 24 2011
%t Table[8 9^Floor[(n-1)/2],{n,50}] (* _Harvey P. Dale_, Oct 21 2011 *)
%Y Cf. A050683.
%Y Cf. A055275.
%K nonn,base,easy
%O 1,1
%A _Martin Renner_, May 02 2006
%E More terms from _Harvey P. Dale_, Oct 21 2011