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.

A226438 Number of permutations of {1..n} with fewer than 5 interior elements having values lying between the values of their neighbors.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 120
6 720
7 5038
8 40066
9 353556
10 3399246
11 35142546
12 387129588
13 4515261680
14 55502974820
15 716557285110
16 9689420220510
17 136922907564972
18 2018121531850482
19 30972340185946810
20 494190208052390752
21 8186609585709287112
22 140620153367124829272

List of values

[1, 1, 2, 6, 24, 120, 720, 5038, 40066, 353556, 3399246, 35142546, 387129588, 4515261680, 55502974820, 716557285110, 9689420220510, 136922907564972, 2018121531850482, 30972340185946810, 494190208052390752, 8186609585709287112, 140620153367124829272]

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

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