A324917 - OEIS

A324917

a(n) = A134664(n) mod 2.

1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

COMMENTS

It would be nice to have an alternative characterization of this sequence.

LINKS

Table of n, a(n) for n=1..87.

C. Defant, Counting 3-stack-sortable permutations, arXiv:1903.09138 [math.CO], 2019.

M. Elder and V. Vatter, Problems and Conjectures presented at the Third International Conference on Permutation Patterns, University of Florida, March 7-11, 2005, arXiv:math/0505504 [math.CO], 2005.

EXAMPLE

There are 114 3-stack-sortable permutations of {1,2,3,4,5}. Since 114 is even, a(5)=0.

CROSSREFS

Cf. A134664, A324964.