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 A193937 #19 Jun 14 2020 09:42:34 %S A193937 1,2,6,24,120,720,5040,40320,362880,3628800,39916680,478991641, %T A193937 6226516930,87157924751,1306945300264 %N A193937 6-nonnesting permutations. %C A193937 Also the number of 6-noncrossing permutations. %H A193937 Sophie Burrill, Sergi Elizalde, Marni Mishna and Lily Yen, <a href="http://arxiv.org/abs/1108.5615">A generating tree approach to k-nonnesting partitions and permutations</a>, arXiv preprint arXiv:1108.5615 [math.CO], 2011-2014. %H A193937 S. Corteel, <a href="http://dx.doi.org/10.1016/j.aam.2006.01.006">Crossings and alignments of permutations</a>, Adv. Appl. Math 38 (2007) 149-163. %Y A193937 Cf. A193938, A193935, A193936. %K A193937 nonn,more %O A193937 1,2 %A A193937 _Lily Yen_, Aug 09 2011