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 A056631 #8 Apr 26 2022 20:54:49 %S A056631 1,8,70,560,4358,33160,248998,1851040,13655432,100126648,730548788, %T A056631 5308524968,38442000664,277565593032,1999068564026,14365917755936, %U A056631 103038218758426,737765745264544,5274413814993896,37655943519835560 %N A056631 a(n) is the total second area moment of all self-avoiding polygons of length 2n on the square lattice. %H A056631 I. Jensen, <a href="/A056631/b056631.txt">Table of n, a(n) for n = 2..43</a> (from link below) %H A056631 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/polygons/series/square.area_mom2.ser">More terms</a> %Y A056631 Cf. A002931, A056625. %K A056631 nonn %O A056631 2,2 %A A056631 _N. J. A. Sloane_, Aug 30 2000 %E A056631 Title clarified by _Sean A. Irvine_, Apr 26 2022