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 A056625 #8 Apr 25 2022 22:35:20 %S A056625 1,4,22,124,726,4352,26614,165204,1037672,6580424,42062040,270661328, %T A056625 1751614248,11391756176,74406502814,487838450116,3209229661682, %U A056625 21175301453040,140097533633112,929160187609096 %N A056625 a(n) is the total area of all self-avoiding polygons of length 2n on the square lattice. %H A056625 I. Jensen, <a href="/A056625/b056625.txt">Table of n, a(n) for n = 2..43</a> (from link below) %H A056625 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/polygons/series/square.area_mom1.ser">More terms</a> %Y A056625 Cf. A002931, A056631. %K A056625 nonn %O A056625 2,2 %A A056625 _N. J. A. Sloane_, Aug 30 2000 %E A056625 Title clarified by _Sean A. Irvine_, Apr 25 2022