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.

A228396 The number of permutations of length n sortable by 2 reversals.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 22
5 63
6 145
7 288
8 516
9 857
10 1343
11 2010
12 2898
13 4051
14 5517
15 7348
16 9600
17 12333
18 15611
19 19502
20 24078
21 29415
22 35593
23 42696
24 50812
25 60033
26 70455
27 82178
28 95306
29 109947
30 126213
31 144220
32 164088
33 185941
34 209907
35 236118
36 264710
37 295823
38 329601
39 366192
40 405748

List of values

[1, 1, 2, 6, 22, 63, 145, 288, 516, 857, 1343, 2010, 2898, 4051, 5517, 7348, 9600, 12333, 15611, 19502, 24078, 29415, 35593, 42696, 50812, 60033, 70455, 82178, 95306, 109947, 126213, 144220, 164088, 185941, 209907, 236118, 264710, 295823, 329601, 366192, 405748]