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.

A111281 Number of permutations avoiding the patterns {2413,2431,4213,3412,3421,4231,4321,4312}; number of strong sorting class based on 2413.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 16
5 40
6 100
7 252
8 636
9 1604
10 4044
11 10196
12 25708
13 64820
14 163436
15 412084
16 1039020
17 2619764
18 6605420
19 16654772
20 41993004
21 105880308
22 266964460
23 673118772
24 1697188012
25 4279255412
26 10789627756
27 27204748468
28 68593500716
29 172950260724
30 436073277676

List of values

[1, 1, 2, 6, 16, 40, 100, 252, 636, 1604, 4044, 10196, 25708, 64820, 163436, 412084, 1039020, 2619764, 6605420, 16654772, 41993004, 105880308, 266964460, 673118772, 1697188012, 4279255412, 10789627756, 27204748468, 68593500716, 172950260724, 436073277676]

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

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