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.

A248087 Number of n-derangements that have an odd number of 2-cycles.

Table of values

n a(n)
0 0
1 0
2 1
3 0
4 0
5 20
6 105
7 504
8 4480
9 43560
10 424305
11 4613840
12 55668096
13 724667580
14 10136511385
15 152029000200
16 2432747715840
17 41357024915024
18 744416488494945
19 14143911946532640
20 282878618744592640
21 5940450667217358180
22 130689899053015493961
23 3005867708207562586520

List of values

[0, 0, 1, 0, 0, 20, 105, 504, 4480, 43560, 424305, 4613840, 55668096, 724667580, 10136511385, 152029000200, 2432747715840, 41357024915024, 744416488494945, 14143911946532640, 282878618744592640, 5940450667217358180, 130689899053015493961, 3005867708207562586520]

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

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