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.

A165542 Number of permutations of length n which avoid the patterns 4231 and 4123.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 22
5 89
6 380
7 1677
8 7566
9 34676
10 160808
11 752608
12 3548325
13 16830544
14 80234659
15 384132724
16 1845829988
17 8897740300
18 43010084460
19 208409687323
20 1012046126532
21 4923952560917
22 23997719075657
23 117136530812812
24 572552052378494
25 2802078324448067

List of values

[1, 1, 2, 6, 22, 89, 380, 1677, 7566, 34676, 160808, 752608, 3548325, 16830544, 80234659, 384132724, 1845829988, 8897740300, 43010084460, 208409687323, 1012046126532, 4923952560917, 23997719075657, 117136530812812, 572552052378494, 2802078324448067]

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

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