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 A087519 #4 Mar 31 2012 12:35:00 %S A087519 1,16,3584,58566144 %N A087519 Number of arrangements of 1..n^2 in n X n array with one local minimum and one local maximum. %C A087519 Neighbors of a cell are only considered in the X and Y directions. %e A087519 For n=2, 12 has one local max. whereas 13 has two local maxima %e A087519 ........ 34 and one local min. ....... 42 and two local minima %Y A087519 Cf. A087518. %K A087519 nonn,nice %O A087519 1,2 %A A087519 _R. H. Hardin_, Oct 23 2003