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 A055899 #10 Aug 16 2021 13:56:51
%S A055899 1,7,31,101,272,636,1340,2600,4725,8135,13391,21217,32536,48496,70512,
%T A055899 100296,139905,191775,258775,344245,452056,586652,753116,957216,
%U A055899 1205477,1505231,1864695,2293025,2800400,3398080,4098496,4915312
%N A055899 Column 3 of triangle A055898.
%H A055899 A. J. Guttmann, <a href="https://doi.org/10.1016/S0012-365X(99)00262-9">Indicators of solvability for lattice models</a>, Discrete Math., 217 (2000), 167-189 (H_3 for square lattices of Section 6).
%F A055899 G.f.: x^3(1+2x+4x^2+2x^3+x^4)/((1-x)^7(1+x)^2). [Corrected by _Georg Fischer_, Aug 16 2021]
%t A055899 CoefficientList[Series[(1+2*x+4*x^2+2*x^3+x^4)/((1-x)^7*(1+x)^2), {x, 0, 40}], x] (* _Georg Fischer_, Aug 16 2021 *)
%Y A055899 Cf. A055898 (triangle), A055900 (column 4), A055901 (5), A055902 (6), A055903 (7), A055904 (8).
%K A055899 nonn,easy
%O A055899 3,2
%A A055899 _Christian G. Bower_, Jun 13 2000