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 A075222 #11 Dec 05 2014 02:44:05 %S A075222 0,0,0,0,0,0,2,10,22,54,52,534,523,1339,3218,9315,2177,29426,15423, %T A075222 101314,140072,110794,46748,1639279,710736,970251,3002062,8462256, %U A075222 895291,29458807 %N A075222 Number of polyiamonds with n cells that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion). %C A075222 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 A075222 Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4. %H A075222 Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyiamond tiling</a> %Y A075222 Cf. A071332, A075216, A075217, A075218, A075219, A075220, A075221, A075223, A075224, A075204, A075213. %K A075222 hard,nonn %O A075222 1,7 %A A075222 _Joseph Myers_, Sep 08 2002 %E A075222 More terms from _Joseph Myers_, Nov 11 2003 %E A075222 a(29) and a(30) from _Joseph Myers_, Nov 21 2010