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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.

A322255 Triangle T(n,k) giving the number of permutations of 1..n with no adjacent elements within k in value, for n >= 2, 1 <= k <= floor(n/2).

Table of values

n a(n)
2 2
3 6
4 24
5 2
6 120
7 14
8 720
9 90
10 2
11 5040
12 646
13 32
14 40320
15 5242
16 368
17 2
18 362880
19 47622
20 3984
21 72
22 3628800
23 479306
24 44304
25 1496
26 2
27 39916800
28 5296790
29 521606
30 25384
31 160
32 479001600
33 63779034
34 6564318
35 399848
36 6056
37 2
38 6227020800
39 831283558
40 88422296
41 6231544
42 161136
43 352

List of values

[2, 6, 24, 2, 120, 14, 720, 90, 2, 5040, 646, 32, 40320, 5242, 368, 2, 362880, 47622, 3984, 72, 3628800, 479306, 44304, 1496, 2, 39916800, 5296790, 521606, 25384, 160, 479001600, 63779034, 6564318, 399848, 6056, 2, 6227020800, 831283558, 88422296, 6231544, 161136, 352]

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

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