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 A075209 #11 Dec 05 2014 02:19:35 %S A075209 1,1,3,6,12,36,59,208,373,1024,1380,5966,6012,20061,32939,91715,99540, %T A075209 381899,390781,1486746,1856858 %N A075209 Number of polyhexes with n cells that tile the plane both by translation and by 180-degree rotation (Conway criterion). %D A075209 Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4. %H A075209 Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyhex tiling</a> %Y A075209 Cf. A070766, A075207, A075208, A075210, A075211, A075212, A075213, A075214, A075215, A075200, A075218. %K A075209 hard,nonn %O A075209 1,3 %A A075209 _Joseph Myers_, Sep 08 2002 %E A075209 More terms from _Joseph Myers_, Nov 08 2003 %E A075209 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 05 2007