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.

A177531 Number of permutations of {1,...,n} avoiding adjacent step pattern up, up, down, down, down.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 120
6 710
7 4900
8 38640
9 342720
10 3376800
11 36603975
12 432850200
13 5545086300
14 76500496800
15 1130799033000
16 17829310686875
17 298684478837750
18 5298029559119250
19 99196696006173000
20 1955043380032965000
21 40458045505003152500
22 877115498011253207500

List of values

[1, 1, 2, 6, 24, 120, 710, 4900, 38640, 342720, 3376800, 36603975, 432850200, 5545086300, 76500496800, 1130799033000, 17829310686875, 298684478837750, 5298029559119250, 99196696006173000, 1955043380032965000, 40458045505003152500, 877115498011253207500]

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

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