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 A008910 #5 May 16 2003 03:00:00 %S A008910 0,1,2,9,26,122,466,2299,10316,54179 %N A008910 Join 2n points on a line with n arcs above the line; form graph with the arcs as nodes, joining 2 nodes when the arcs cross. a(n) is the number of cases in which the graph is symmetric about middle and has no isolated nodes. %K A008910 nonn %O A008910 1,3 %A A008910 klazar(AT)kam.mff.cuni.cz (Martin Klazar)