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 A226301 #19 Nov 04 2019 02:19:26
%S A226301 2,20,210,2460,31122,410378,5575682,77445152,1093987598,15660579168,
%T A226301 226608224226,3308255447206,48658330768786,720224064591558,
%U A226301 10718841444208526,160283814975116386,2406806389622598056,36273856567768931782,548495166665709003794,8318227159058988730096
%N A226301 a(n) = A182107(4n+1).
%H A226301 Alejandro Erickson, Frank Ruskey, <a href="http://arxiv.org/abs/1304.0070">Enumerating maximal tatami mat coverings of square grids with v vertical dominoes</a>, arXiv:1304.0070 [math.CO], 2013.
%t A226301 S[0, 0] = 1; S[0, _] = 0; S[n_, k_] /; k < 0 || k > Binomial[n + 1, 2] = 0; S[n_, k_] := S[n, k] = S[n - 1, k] + S[n - 1, k - n];
%t A226301 b[n_] := 2 Sum[Sum[k2 = (n^2 - n)/4 - (n - i - 1) - k1; S[n - i - 2, k1] * S[i - 1, k2], {k1, 0, (n^2 - n)/4 - (n - i - 1)}] + Sum[k2 = (n^2 - n)/4; S[Floor[(n - 2)/2], k1] * S[Floor[(n - 2)/2], k2], {k1, 0, (n^2 - n)/4}], {i, 1, Floor[(n - 1)/2]}];
%t A226301 a[n_] := b[4n+1];
%t A226301 Table[a[n], {n, 1, 20}] (* _Jean-François Alcover_, Feb 23 2019 *)
%Y A226301 Cf. A182107, A226300.
%K A226301 nonn
%O A226301 1,1
%A A226301 _N. J. A. Sloane_, Jun 06 2013