cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A217817 Number of alternating permutations on 2n letters that avoid a certain pattern of length 5 (see Lewis, 2012, Appendix, for precise definition).

Table of values

n a(n)
1 1
2 5
3 56
4 997
5 23653
6 679810
7 22394962
8 816872290

List of values

[1, 5, 56, 997, 23653, 679810, 22394962, 816872290]