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.

A331007 Number of derangements of a set of n elements where 2 specific elements cannot appear in each other's positions.

Table of values

n a(n)
0 1
1 0
2 0
3 0
4 4
5 24
6 168
7 1280
8 10860
9 101976
10 1053136
11 11881152
12 145510740
13 1923678680
14 27313300344
15 414633520704
16 6702860119228
17 114974897260440
18 2085904412222880
19 39909278145297536
20 803157866412577956
21 16960527261105495192
22 375011130469825988680
23 8664636644578485432960

List of values

[1, 0, 0, 0, 4, 24, 168, 1280, 10860, 101976, 1053136, 11881152, 145510740, 1923678680, 27313300344, 414633520704, 6702860119228, 114974897260440, 2085904412222880, 39909278145297536, 803157866412577956, 16960527261105495192, 375011130469825988680, 8664636644578485432960]

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

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