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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.

A385366 a(n) = Sum_{permutations p of [n]} des(p^2), where des(p) is the number of descents of p.

Table of values

n a(n)
1 0
2 0
3 2
4 24
5 192
6 1560
7 13680
8 131040
9 1370880
10 15603840
11 192326400
12 2554675200
13 36404121600
14 554204851200
15 8979363993600
16 154305575424000
17 2803653844992000
18 53708801642496000
19 1082001156268032000
20 22869278876860416000
21 506043617700741120000
22 11699825757321461760000

List of values

[0, 0, 2, 24, 192, 1560, 13680, 131040, 1370880, 15603840, 192326400, 2554675200, 36404121600, 554204851200, 8979363993600, 154305575424000, 2803653844992000, 53708801642496000, 1082001156268032000, 22869278876860416000, 506043617700741120000, 11699825757321461760000]

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

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