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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.

A152885 Number of descents beginning and ending with an odd number in all permutations of {1,2,...,n}.

Table of values

n a(n)
1 0
2 0
3 2
4 6
5 72
6 360
7 4320
8 30240
9 403200
10 3628800
11 54432000
12 598752000
13 10059033600
14 130767436800
15 2440992153600
16 36614882304000
17 753220435968000
18 12804747411456000
19 288106816757760000
20 5474029518397440000
21 133809610449715200000
22 2810001819444019200000

List of values

[0, 0, 2, 6, 72, 360, 4320, 30240, 403200, 3628800, 54432000, 598752000, 10059033600, 130767436800, 2440992153600, 36614882304000, 753220435968000, 12804747411456000, 288106816757760000, 5474029518397440000, 133809610449715200000, 2810001819444019200000]

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

Content is available under The OEIS End-User License Agreement.