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 A265106 #22 Feb 09 2020 12:08:06
%S A265106 0,1,2,6,16,36,80,178,394,870,1920,4236,9344,20610,45458,100262,
%T A265106 221136,487732,1075728,2372594,5232922,11541574,25455744,56144412,
%U A265106 123830400,273116546,602377506,1328585414,2930287376,6462952260,14254489936,31439267250,69341486762
%N A265106 Expansion of (x^5-x^4-2*x^3+x^2-x)/(-x^4+x^3-2*x^2+3*x-1).
%H A265106 Colin Barker, <a href="/A265106/b265106.txt">Table of n, a(n) for n = 0..1000</a>
%H A265106 M. Diepenbroek, M. Maus, A. Stoll, <a href="http://www.valpo.edu/mathematics-statistics/files/2014/09/Pudwell2015.pdf">Pattern Avoidance in Reverse Double Lists</a>, Preprint 2015. See Table 3.
%H A265106 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2,1,-1).
%F A265106 a(n) = 3*a(n-1)-2*a(n-2)+a(n-3)-a(n-4) for n>5. - _Colin Barker_, Apr 12 2016
%F A265106 a(n) = 2*a(n-1) + a(n-3) + 2 for n>4. - _Greg Dresden_, Feb 09 2020
%t A265106 CoefficientList[Series[(x^5-x^4-2x^3+x^2-x)/(-x^4+x^3-2x^2+3x-1),{x,0,40}],x] (* or *) LinearRecurrence[{3,-2,1,-1},{0,1,2,6,16,36},40] (* _Harvey P. Dale_, Feb 05 2019 *)
%o A265106 (PARI) concat(0, Vec(x*(1-x+2*x^2+x^3-x^4)/((1-x)*(1-2*x-x^3)) + O(x^50))) \\ _Colin Barker_, Apr 12 2016
%Y A265106 Cf. A002605, A265107, A265278, A270810.
%K A265106 nonn,easy
%O A265106 0,3
%A A265106 _Alois P. Heinz_, Apr 06 2016