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 A026655 #13 Oct 29 2022 09:09:01
%S A026655 1,2,5,10,22,44,98,196,436,872,1940,3880,8632,17264,38408,76816,
%T A026655 170896,341792,760400,1520800,3383392,6766784,15054368,30108736,
%U A026655 66984256,133968512,298045760,596091520,1326151552,2652303104
%N A026655 T(n,0) + T(n,1) + ... + T(n,n), T given by A026648.
%H A026655 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,4,0,2)
%F A026655 G.f.: ((1+2x)*(1+x^2))/(1-4x^2-2x^4). - _Ralf Stephan_, Apr 30 2004
%t A026655 CoefficientList[Series[((1+2x)(1+x^2))/(1-4x^2-2x^4),{x,0,45}], x] (* _Harvey P. Dale_, Mar 15 2011 *)
%Y A026655 Cf. A026648.
%K A026655 nonn
%O A026655 0,2
%A A026655 _Clark Kimberling_