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 A054136 #9 Mar 29 2024 14:07:01
%S A054136 2,6,18,46,107,235,498,1032,2109,4273,8612,17302,34695,69495,139110,
%T A054136 278356,556865,1113901,2227992,4456194,8912619,17825491,35651258,
%U A054136 71302816,142605957,285212265,570424908,1140850222,2281700879
%N A054136 a(n) = T(n,2), array T as in A054134.
%H A054136 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (5,-9,7,-2).
%F A054136 G.f.: x^2(x^4-4x^3+6x^2-4x+2)/[(1-2x)(1-x)^3].
%t A054136 Drop[CoefficientList[Series[x^2(x^4-4x^3+6x^2-4x+2)/((1-2x)(1-x)^3),{x,0,30}],x],2] (* or *) LinearRecurrence[{5,-9,7,-2},{2,6,18,46,107},40] (* _Harvey P. Dale_, Mar 29 2024 *)
%Y A054136 Cf. A054134.
%K A054136 nonn,easy
%O A054136 2,1
%A A054136 _Clark Kimberling_