A224318 Number of 2-vexillary permutations in S_n, that, permutations whose Stanley symmetric function has at most 2 terms or at most 2 Edelman-Greene tableaux.

1, 1, 2, 6, 24, 118, 661, 4011, 25654, 170420, 1165697

Offset

0,3

Comments

This family is characterized by a finite set of permutation patterns.

Links

Table of n, a(n) for n=0..10.

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, A223905, A224287.

Sequence in context: A228397 A164871 A226436 * A079106 A247472 A224295

Adjacent sequences: A224315 A224316 A224317 * A224319 A224320 A224321

Keyword

nonn,more

Author

Sara Billey, Apr 03 2013

Extensions

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

Status

approved