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 A075199 #12 Dec 05 2014 03:04:38 %S A075199 0,0,0,0,0,0,0,0,1,2,10,135,142,591,2667,5291,6863,35876,34819,161812, %T A075199 272329,454465,651720,3441853,3442733 %N A075199 Number of polyominoes with n cells that tile the plane by translation but not by 180-degree rotation (Conway criterion). %D A075199 Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4. %H A075199 Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyomino tiling</a> %Y A075199 Cf. A054359, A075198, A075200, A075201, A075202, A075203, A075204, A075205, A075206, A075208, A075217. %K A075199 hard,nonn %O A075199 1,10 %A A075199 _Joseph Myers_, Sep 08 2002 %E A075199 More terms from _Joseph Myers_, Nov 04 2003 %E A075199 a(24) and a(25) from _Joseph Myers_, Nov 17 2010