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

Offset

1

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.

Sequence in context: A358777 A359595 A353557 * A369974 A369975 A369001

Adjacent sequences: A324914 A324915 A324916 * A324918 A324919 A324920

Keyword

nonn

Author

Colin Defant, Mar 18 2019

Status

approved