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.

A097971 Number of alternating runs in all permutations of [n] (the permutation 732569148 has four alternating runs: 732, 2569, 91 and 148).

Table of values

n a(n)
2 2
3 10
4 56
5 360
6 2640
7 21840
8 201600
9 2056320
10 22982400
11 279417600
12 3672345600
13 51891840000
14 784604620800
15 12640852224000
16 216202162176000
17 3912561709056000
18 74694359900160000
19 1500289571708928000
20 31627726106296320000
21 698242876346695680000

List of values

[2, 10, 56, 360, 2640, 21840, 201600, 2056320, 22982400, 279417600, 3672345600, 51891840000, 784604620800, 12640852224000, 216202162176000, 3912561709056000, 74694359900160000, 1500289571708928000, 31627726106296320000, 698242876346695680000]

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

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