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.

A278639 Number of pairs of orientable necklaces with n beads and up to 3 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 1
4 3
5 12
6 38
7 117
8 336
9 976
10 2724
11 7689
12 21455
13 60228
14 168714
15 475037
16 1338861
17 3788400
18 10742588
19 30556305
20 87112059
21 248967564
22 713032782
23 2046325125
24 5883428618
25 16944975048
26 48880471500
27 141212377489
28 408509453511
29 1183275193908
30 3431504760514

List of values

[0, 0, 0, 1, 3, 12, 38, 117, 336, 976, 2724, 7689, 21455, 60228, 168714, 475037, 1338861, 3788400, 10742588, 30556305, 87112059, 248967564, 713032782, 2046325125, 5883428618, 16944975048, 48880471500, 141212377489, 408509453511, 1183275193908, 3431504760514]

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

Content is available under The OEIS End-User License Agreement.