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.

A260074 Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by two: p(i)<>i and (i-p(i) mod n <= 2 or p(i)-i mod n <= 2).

Table of values

n a(n)
0 1
1 0
2 1
3 2
4 9
5 44
6 80
7 144
8 260
9 448
10 808
11 1456
12 2640
13 4788
14 8744
15 16016
16 29444
17 54268
18 100304
19 185824
20 344996
21 641664
22 1195400
23 2230176
24 4165904
25 7790244
26 14581640
27 27316240
28 51209124
29 96060300
30 180291280
31 338538480
32 635940356
33 1195021888
34 2246289704

List of values

[1, 0, 1, 2, 9, 44, 80, 144, 260, 448, 808, 1456, 2640, 4788, 8744, 16016, 29444, 54268, 100304, 185824, 344996, 641664, 1195400, 2230176, 4165904, 7790244, 14581640, 27316240, 51209124, 96060300, 180291280, 338538480, 635940356, 1195021888, 2246289704]

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

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