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 A255489 #3 Mar 01 2015 23:24:52 %S A255489 1,5,36,295,2583,23580,221680 %N A255489 Row 3 of array in A211400. %C A255489 Row 2 gives the Catalan numbers, which automatically makes row 3 interesting. %Y A255489 Cf. A000108, A211400. %K A255489 nonn,more %O A255489 1,2 %A A255489 _N. J. A. Sloane_, Mar 01 2015