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 A239757 #9 Jul 18 2014 12:38:59 %S A239757 1,1,8,141,4192,178225,10218096,762401773 %N A239757 Number of pairs of functions (f,g) from a set of n elements into itself satisfying f(g(g(x))) = g(f(f(x))). %Y A239757 Cf. A000248, A000949. %K A239757 nonn,more %O A239757 0,3 %A A239757 _Chad Brewbaker_, Mar 26 2014 %E A239757 a(6)-a(7) from _Giovanni Resta_, Mar 28 2014