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 A057407 #12 Jul 19 2014 01:09:42 %S A057407 2,36,366,2832,18666,110724,609922,3182038,15931446,77253554, %T A057407 365240626,1691895678,7707586246,34630458076,153803559514, %U A057407 676416563354,2949990640350,12772844235264,54957447470264 %N A057407 Number of self-avoiding polygons of area n with 2 (self-avoiding polygon) holes on square lattice (not allowing rotations). %H A057407 I. Jensen, <a href="/A057407/b057407.txt">Table of n, a(n) for n = 13..44</a> (from link below) %H A057407 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/polygons/series/square.area.2hole.ser">More terms</a> %K A057407 nonn %O A057407 13,1 %A A057407 _N. J. A. Sloane_, Aug 30 2000