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 A075213 #10 Dec 05 2014 02:41:31 %S A075213 0,0,0,0,1,1,33,88,611,1803,2985,21250,23564,100221,392655,438188, %T A075213 433150,4762862,2327445,18839643,46717154 %N A075213 Number of polyhexes with n cells that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion). %C A075213 A tiling is isohedral if the symmetries of the tiling act transitively on the tiles; a shape is anisohedral if it tiles the plane, but not isohedrally. %D A075213 Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4. %H A075213 Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyhex tiling</a> %Y A075213 Cf. A070766, A075207, A075208, A075209, A075210, A075211, A075212, A075214, A075215, A075204, A075222. %K A075213 hard,nonn %O A075213 1,7 %A A075213 _Joseph Myers_, Sep 08 2002 %E A075213 More terms from _Joseph Myers_, Nov 08 2003 %E A075213 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 05 2007