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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.

A145219 a(n) is the number of even permutations (of an n-set) with exactly 1 fixed point.

Table of values

n a(n)
1 1
2 0
3 0
4 8
5 15
6 144
7 910
8 7440
9 66717
10 667520
11 7342236
12 88107480
13 1145396395
14 16035550608
15 240533257770
16 3848532125984
17 65425046139705
18 1177650830517120
19 22375365779822392
20 447507315596451240
21 9397653627525472071
22 206748379805560390160
23 4755212735527888968390

List of values

[1, 0, 0, 8, 15, 144, 910, 7440, 66717, 667520, 7342236, 88107480, 1145396395, 16035550608, 240533257770, 3848532125984, 65425046139705, 1177650830517120, 22375365779822392, 447507315596451240, 9397653627525472071, 206748379805560390160, 4755212735527888968390]

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

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