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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.

A278642 Number of pairs of orientable necklaces with n beads and up to 6 colors; i.e., turning the necklace over does not leave it unchanged. The turned-over necklace is not included in the count.

Table of values

n a(n)
0 0
1 0
2 0
3 20
4 105
5 672
6 3535
7 19350
8 102795
9 556010
10 3010098
11 16467450
12 90619690
13 502194420
14 2798240265
15 15671993560
16 88156797855
17 497837886000
18 2821092554035
19 16035752398770
20 91403856697944
21 522308167195260
22 2991401733402075
23 17168047238861070
24 98716274117752900
25 568605754068247644
26 3280417827002225910
27 18953525314104758810

List of values

[0, 0, 0, 20, 105, 672, 3535, 19350, 102795, 556010, 3010098, 16467450, 90619690, 502194420, 2798240265, 15671993560, 88156797855, 497837886000, 2821092554035, 16035752398770, 91403856697944, 522308167195260, 2991401733402075, 17168047238861070, 98716274117752900, 568605754068247644, 3280417827002225910, 18953525314104758810]

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

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