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.

A208529 Number of permutations of n > 1 having exactly 2 points on the boundary of their bounding square.

Table of values

n a(n)
2 2
3 2
4 4
5 12
6 48
7 240
8 1440
9 10080
10 80640
11 725760
12 7257600
13 79833600
14 958003200
15 12454041600
16 174356582400
17 2615348736000
18 41845579776000
19 711374856192000
20 12804747411456000
21 243290200817664000
22 4865804016353280000
23 102181884343418880000

List of values

[2, 2, 4, 12, 48, 240, 1440, 10080, 80640, 725760, 7257600, 79833600, 958003200, 12454041600, 174356582400, 2615348736000, 41845579776000, 711374856192000, 12804747411456000, 243290200817664000, 4865804016353280000, 102181884343418880000]

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

Content is available under The OEIS End-User License Agreement.