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 A239756 #9 Jul 18 2014 12:37:18 %S A239756 1,1,8,129,3616,151845,8864496,682005919 %N A239756 Number of pairs of functions (f,g) from a set of n elements into itself satisfying f(f(g(x))) = g(g(x)). %Y A239756 Cf. A000248, A000949. %K A239756 nonn,more %O A239756 0,3 %A A239756 _Chad Brewbaker_, Mar 26 2014 %E A239756 a(6)-a(7) from _Giovanni Resta_, Mar 28 2014