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.

A107763 Number of ways to arrange the numbers (1,3,5,7,9,...,2n-1) in a circle such that every two adjacent numbers are relatively prime.

Table of values

n a(n)
1 1
2 1
3 2
4 6
5 12
6 72
7 480
8 864
9 9600
10 108000
11 312000
12 4795200
13 46293120
14 241056000
15 4759413120
16 94182359040
17 478511953920
18 4873965022080
19 122634632171520
20 799554193966080
21 23063946114908160
22 664424069072117760
23 3198456730188840960
24 108184656752428032000
25 2657146152621477888000
26 22850984107452933734400
27 863305241854715928576000
28 15282315334192501724774400
29 151673086024479840160972800

List of values

[1, 1, 2, 6, 12, 72, 480, 864, 9600, 108000, 312000, 4795200, 46293120, 241056000, 4759413120, 94182359040, 478511953920, 4873965022080, 122634632171520, 799554193966080, 23063946114908160, 664424069072117760, 3198456730188840960, 108184656752428032000, 2657146152621477888000, 22850984107452933734400, 863305241854715928576000, 15282315334192501724774400, 151673086024479840160972800]

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

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