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 A054360 #10 Mar 30 2012 17:28:41 %S A054360 0,0,0,0,0,0,4,26,235,1585,10453,40151,199922,792867,3146993,12532362, %T A054360 49280874,189564720,739243108,2858545267,11101139486,43154849550, %U A054360 167993679964,654778791594,2556955750961 %N A054360 Number of polyominoes with n cells that do not tile the plane. %D A054360 Posting by Glenn C. Rhoads (rhoads(AT)paul.rutgers.edu) to rec.puzzles, Feb 17 2000. %H A054360 Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyomino tiling</a> %e A054360 a(7) = 4. %Y A054360 Cf. A000105, A054359, A054361. %K A054360 nonn,hard %O A054360 1,7 %A A054360 Joe Keane (jgk(AT)jgk.org) %E A054360 Corrected and extended by _Joseph Myers_, May 05 2002 %E A054360 More terms from _Joseph Myers_, Nov 04 2003 %E A054360 a(24) and a(25) from _Joseph Myers_, Nov 17 2010