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.

A152875 Number of permutations of {1,2,...,n} with all odd entries preceding all even entries or all even entries preceding all odd entries.

Table of values

n a(n)
0 1
1 1
2 2
3 4
4 8
5 24
6 72
7 288
8 1152
9 5760
10 28800
11 172800
12 1036800
13 7257600
14 50803200
15 406425600
16 3251404800
17 29262643200
18 263363788800
19 2633637888000
20 26336378880000
21 289700167680000
22 3186701844480000
23 38240422133760000
24 458885065605120000
25 5965505852866560000

List of values

[1, 1, 2, 4, 8, 24, 72, 288, 1152, 5760, 28800, 172800, 1036800, 7257600, 50803200, 406425600, 3251404800, 29262643200, 263363788800, 2633637888000, 26336378880000, 289700167680000, 3186701844480000, 38240422133760000, 458885065605120000, 5965505852866560000]

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

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