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.

A167406 Sequence a(n) gives the number of ways to seat 2n people around a circular table so that person i does not sit across from person n+i for any 1 <= i <= n.

Table of values

n a(n)
1 0
2 4
3 64
4 2880
5 208896
6 23193600
7 3640688640
8 768126320640
9 209688566169600
10 71921062285148160
11 30278182590480384000
12 15350836256712740044800
13 9225766813653105691852800
14 6485670333458406942179328000
15 5272823572160895949091320627200

List of values

[0, 4, 64, 2880, 208896, 23193600, 3640688640, 768126320640, 209688566169600, 71921062285148160, 30278182590480384000, 15350836256712740044800, 9225766813653105691852800, 6485670333458406942179328000, 5272823572160895949091320627200]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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