A223905 Number of 4-vexillary permutations in S_n, that is, permutations whose Stanley symmetric function has at most 4 terms or at most 4 Edelman-Greene tableaux.

1, 1, 2, 6, 24, 120, 717, 4824, 34629, 256689, 1935301

Offset: 0

Author

Sara Billey, Apr 04 2013

Keywords

• nonn
• more

Comments

This family is characterized by a finite set of patterns.

Links

• S. Billey and B. Pawlowski, Permutation Patterns, Stanley symmetric functions and generalized Specht modules, arXiv:1304.7870 [math.CO], 2013.
• Elizabeth Hartung, Hung Phuc Hoang, Torsten Mütze, Aaron Williams, Combinatorial generation via permutation languages. I. Fundamentals, arXiv:1906.06069 [cs.DM], 2019.

Crossrefs

Cf. A005802, A224318.

Extensions

a(0)=1 prepended by Alois P. Heinz, Jul 31 2019