%I #25 Nov 29 2019 11:59:16
%S 1,1,2,6,24,120,705,4553,30930,216412,1545469
%N 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 This family is characterized by a finite set of permutation patterns.
%H 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 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 Cf. A005802, A223905, A224318, A224287.
%K nonn,more
%O 0,3
%A _Sara Billey_, Apr 04 2013
%E a(0)=1 prepended by _Alois P. Heinz_, Jul 31 2019
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