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.

A095817 Number of permutations of 1..n with no four elements in correct or reverse order.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 22
5 114
6 692
7 4884
8 39318
9 355490
10 3567292
11 39345804
12 473148014
13 6161310442
14 86376341412
15 1297099489668
16 20772929663254
17 353415786538434
18 6365693021157116
19 121016486728717740
20 2421505946364174606
21 50873034832373299370
22 1119617627206173146308

List of values

[1, 1, 2, 6, 22, 114, 692, 4884, 39318, 355490, 3567292, 39345804, 473148014, 6161310442, 86376341412, 1297099489668, 20772929663254, 353415786538434, 6365693021157116, 121016486728717740, 2421505946364174606, 50873034832373299370, 1119617627206173146308]

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

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