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 A286913 #15 Feb 16 2025 08:33:45
%S A286913 0,7,969,2180738,68534828391,30833670159649637,
%T A286913 197887615273032627789510,18126687290150589819559507400227,
%U A286913 23696879029605485832353513435527035363501,442121584517675331278913696274915728729945474905362
%N A286913 Number of edge covers in the grid graph P_n X P_n.
%H A286913 Jean-François Alcover, <a href="/A286913/b286913.txt">Table of n, a(n) for n = 1..12</a>
%H A286913 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/EdgeCover.html">Edge Cover</a>
%H A286913 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GridGraph.html">Grid Graph</a>
%t A286913 A286912 = Cases[Import["https://oeis.org/A286912/b286912.txt", "Table"], {_, _}][[All, 2]];
%t A286913 a[n_] := A286912[[2 n^2 - 2 n + 1]]; a[1] = 1;
%t A286913 Table[a[n], {n, 1, 12}] (* _Jean-François Alcover_, Sep 23 2019 *)
%Y A286913 Main diagonal of A286912.
%Y A286913 Cf. A286911.
%K A286913 nonn
%O A286913 1,2
%A A286913 _Andrew Howroyd_, May 15 2017
%E A286913 a(1) corrected by _Andrew Howroyd_, Jan 29 2023