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.

A177526 Number of permutations of {1,...,n} avoiding adjacent step pattern up, down, down, up, down.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 120
6 680
7 4480
8 33600
9 285434
10 2684680
11 27812170
12 313926560
13 3842611240
14 50625902600
15 714873188122
16 10764733339179
17 172258243070682
18 2918333808555034
19 52191694000877878
20 982479378895814520
21 19419959862935129834
22 402131210857811703926

List of values

[1, 1, 2, 6, 24, 120, 680, 4480, 33600, 285434, 2684680, 27812170, 313926560, 3842611240, 50625902600, 714873188122, 10764733339179, 172258243070682, 2918333808555034, 52191694000877878, 982479378895814520, 19419959862935129834, 402131210857811703926]

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

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