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.

A177528 Number of permutations of {1,...,n} avoiding adjacent step pattern up, down, up, down, down.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 120
6 685
7 4550
8 34440
9 292320
10 2746800
11 28402925
12 320224500
13 3909695400
14 51396618000
15 723952593000
16 10876269801125
17 173607227828250
18 2934111079914750
19 52343975053683000
20 982945842995115000
21 19381240178451775625
22 400347201716808478750

List of values

[1, 1, 2, 6, 24, 120, 685, 4550, 34440, 292320, 2746800, 28402925, 320224500, 3909695400, 51396618000, 723952593000, 10876269801125, 173607227828250, 2934111079914750, 52343975053683000, 982945842995115000, 19381240178451775625, 400347201716808478750]

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

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