This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A081193 #11 Sep 08 2022 08:45:09
%S A081193 1,9,46,204,856,3504,14176,57024,228736,916224,3667456,14674944,
%T A081193 58710016,234860544,939483136,3758014464,15032221696,60129214464,
%U A081193 240517513216,962071363584,3848288075776,15393157545984,61572640669696
%N A081193 a(n) = 6*a(n-1)-8*a(n-2) for n>1, a(0)=1, a(1)=9.
%C A081193 Third binomial transform of A010687 (period 2: repeat 1,6). [_Bruno Berselli_, Aug 06 2013]
%H A081193 Vincenzo Librandi, <a href="/A081193/b081193.txt">Table of n, a(n) for n = 0..200</a>
%H A081193 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,-8).
%F A081193 G.f.: (1+3*x)/((1-2*x)*(1-4*x)).
%F A081193 a(n) = 7*4^n/2-5*2^n/2.
%t A081193 CoefficientList[Series[(1 + 3 x)/((1 - 2 x) (1 - 4 x)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Aug 07 2013 *)
%o A081193 (Magma) [7*4^n/2-5*2^n/2: n in [0..25]]; // _Vincenzo Librandi_, Aug 07 2013
%K A081193 nonn,easy
%O A081193 0,2
%A A081193 _Paul Barry_, Mar 11 2003