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.

A190824 Number of permutations of 2 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 3.

Table of values

n a(n)
0 1
1 0
2 0
3 0
4 1
5 20
6 292
7 4317
8 69862
9 1251584
10 24728326
11 535333713
12 12616277612
13 321762301156
14 8833356675295
15 259803215904436
16 8151872288855008
17 271848098526643604
18 9602477503845334715
19 358185069617609239664
20 14070369448248794118128
21 580623906507508489287367

List of values

[1, 0, 0, 0, 1, 20, 292, 4317, 69862, 1251584, 24728326, 535333713, 12616277612, 321762301156, 8833356675295, 259803215904436, 8151872288855008, 271848098526643604, 9602477503845334715, 358185069617609239664, 14070369448248794118128, 580623906507508489287367]

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

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