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.

A145223 a(n) is the number of odd permutations (of an n-set) with exactly 2 fixed points.

Table of values

n a(n)
2 0
3 0
4 6
5 0
6 90
7 420
8 3780
9 33264
10 333900
11 3670920
12 44054010
13 572697840
14 8017775766
15 120266628300
16 1924266063720
17 32712523068960
18 588825415259640
19 11187682889909904
20 223753657798227150
21 4698826813762734240
22 103374189902780197170
23 2377606367763944481780

List of values

[0, 0, 6, 0, 90, 420, 3780, 33264, 333900, 3670920, 44054010, 572697840, 8017775766, 120266628300, 1924266063720, 32712523068960, 588825415259640, 11187682889909904, 223753657798227150, 4698826813762734240, 103374189902780197170, 2377606367763944481780]

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

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