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 A055582 #18 Sep 28 2023 11:44:55
%S A055582 1,9,48,198,699,2223,6562,18324,49029,126837,319332,786258,1900351,
%T A055582 4521771,10616598,24641280,56622825,128974545,291503800,654311070,
%U A055582 1459617411,3238002279,7147093578,15703473708,34359737869,74893491693
%N A055582 Sixth column of triangle A055252.
%H A055582 Michael De Vlieger, <a href="/A055582/b055582.txt">Table of n, a(n) for n = 0..3296</a>
%H A055582 Robert Davis, Greg Simay, <a href="https://arxiv.org/abs/2001.11089">Further Combinatorics and Applications of Two-Toned Tilings</a>, arXiv:2001.11089 [math.CO], 2020.
%H A055582 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (9, -33, 63, -66, 36, -8).
%F A055582 G.f.: 1/(((1-2*x)^3)*(1-x)^3).
%F A055582 a(n)= A055252(n+5, 5). a(n)= sum(a(j), j=0..n-1)+A034009(n), n >= 1.
%F A055582 a(n)= (n^2 - 3*n + 8)*(2^(n+3) -1)/2 - 9*(n+3). [_Yahia Kahloune_, Aug 11 2013]
%t A055582 CoefficientList[Series[1/(((1 - 2 x)^3) (1 - x)^3), {x, 0, 25}], x] (* _Michael De Vlieger_, Apr 23 2020 *)
%Y A055582 Cf. A055252, A055249, A034009, partial sums of A055581.
%K A055582 easy,nonn
%O A055582 0,2
%A A055582 _Wolfdieter Lang_, May 26 2000