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 A223034 #25 Nov 29 2019 11:59:16 %S A223034 1,1,2,6,24,120,705,4553,30930,216412,1545469 %N A223034 Number of 3-vexillary permutations in S_n, that is, permutations whose Stanley symmetric function has at most 3 terms or at most 3 Edelman-Greene tableaux. %C A223034 This family is characterized by a finite set of permutation patterns. %H A223034 S. Billey and B. Pawlowski, <a href="https://arxiv.org/abs/1304.7870">Permutation Patterns, Stanley symmetric functions and generalized Specht modules</a>, arXiv:1304.7870 [math.CO], 2013. %H A223034 Elizabeth Hartung, Hung Phuc Hoang, Torsten Mütze, Aaron Williams, <a href="https://arxiv.org/abs/1906.06069">Combinatorial generation via permutation languages. I. Fundamentals</a>, arXiv:1906.06069 [cs.DM], 2019. %Y A223034 Cf. A005802, A223905, A224318, A224287. %K A223034 nonn,more %O A223034 0,3 %A A223034 _Sara Billey_, Apr 04 2013 %E A223034 a(0)=1 prepended by _Alois P. Heinz_, Jul 31 2019