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.

A177524 Number of permutations of {1,...,n} avoiding adjacent step pattern up, down, down, down, down.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 120
6 715
7 4970
8 39480
9 352800
10 3502800
11 38255900
12 455795100
13 5883052500
14 81774966000
15 1217871018000
16 19346879737625
17 326549862671250
18 5835951345093750
19 110091785625495000
20 2186122850020215000
21 45580964489553559375
22 995625115672520581250

List of values

[1, 1, 2, 6, 24, 120, 715, 4970, 39480, 352800, 3502800, 38255900, 455795100, 5883052500, 81774966000, 1217871018000, 19346879737625, 326549862671250, 5835951345093750, 110091785625495000, 2186122850020215000, 45580964489553559375, 995625115672520581250]

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

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