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 A057406 #12 Jul 19 2014 01:09:24 %S A057406 1,12,88,524,2786,13788,64998,296032,1314648,5728172,24595512, %T A057406 104399172,439084884,1833027048,7605691356,31398503248,129072844079, %U A057406 528688519536,2158900271080,8792641674684,35728408159781 %N A057406 Number of self-avoiding polygons of area n with one (self-avoiding polygon) hole on square lattice (not allowing rotations). %H A057406 I. Jensen, <a href="/A057406/b057406.txt">Table of n, a(n) for n = 8..41</a> (from link below) %H A057406 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/polygons/series/square.area.1hole.ser">More terms</a> %K A057406 nonn %O A057406 8,2 %A A057406 _N. J. A. Sloane_, Aug 30 2000