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.

A177550 Number of permutations of {1,...,n} avoiding adjacent step pattern up, up, down, up, down, down.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 120
6 720
7 4950
8 38880
9 343440
10 3369600
11 36352800
12 427680000
13 5452027218
14 74846801304
15 1100895311340
16 17272089457920
17 287920937620800
18 5081935953473280
19 94681381716805374
20 1856848184953043760
21 38236452673395920040
22 824863858830361247040

List of values

[1, 1, 2, 6, 24, 120, 720, 4950, 38880, 343440, 3369600, 36352800, 427680000, 5452027218, 74846801304, 1100895311340, 17272089457920, 287920937620800, 5081935953473280, 94681381716805374, 1856848184953043760, 38236452673395920040, 824863858830361247040]

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

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