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.

A239841 Ordered pairs of permutation functions on n elements where f(g(g(x))) = g(g(f(x))).

Table of values

n a(n)
0 1
1 1
2 4
3 30
4 312
5 3720
6 64080
7 1305360
8 33949440
9 1019692800
10 36360576000
11 1487539468800
12 69633899596800
13 3649476307276800
14 213929162589542400
15 13848506938506240000
16 986705192227442688000
17 76724136092268048384000
18 6491471142159880740864000

List of values

[1, 1, 4, 30, 312, 3720, 64080, 1305360, 33949440, 1019692800, 36360576000, 1487539468800, 69633899596800, 3649476307276800, 213929162589542400, 13848506938506240000, 986705192227442688000, 76724136092268048384000, 6491471142159880740864000]

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

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