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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.

A152873 Number of permutations of {1,2,...,n} (n>=2) having a single run of even entries. For example, the permutation 513284679 has a single run of even entries: 2846.

Table of values

n a(n)
2 2
3 6
4 12
5 48
6 144
7 720
8 2880
9 17280
10 86400
11 604800
12 3628800
13 29030400
14 203212800
15 1828915200
16 14631321600
17 146313216000
18 1316818944000
19 14485008384000
20 144850083840000
21 1738201006080000
22 19120211066880000
23 248562743869440000
24 2982752926433280000
25 41758540970065920000

List of values

[2, 6, 12, 48, 144, 720, 2880, 17280, 86400, 604800, 3628800, 29030400, 203212800, 1828915200, 14631321600, 146313216000, 1316818944000, 14485008384000, 144850083840000, 1738201006080000, 19120211066880000, 248562743869440000, 2982752926433280000, 41758540970065920000]

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

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