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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.

A320744 Number of chiral pairs of color patterns (set partitions) in a cycle of length n using 4 or fewer colors (subsets).

Table of values

n a(n)
1 0
2 0
3 0
4 0
5 0
6 6
7 30
8 130
9 532
10 2006
11 7626
12 28401
13 106260
14 396435
15 1486147
16 5580130
17 21032880
18 79486763
19 301317282
20 1145123672
21 4362804633
22 16658456825
23 63738451998
24 244332656201
25 938244497740
26 3608640426930
27 13899977105315
28 53614228550220
29 207061964668740
30 800639722002163
31 3099251007215286
32 12009598156277090
33 46582685655751645
34 180850428684482360

List of values

[0, 0, 0, 0, 0, 6, 30, 130, 532, 2006, 7626, 28401, 106260, 396435, 1486147, 5580130, 21032880, 79486763, 301317282, 1145123672, 4362804633, 16658456825, 63738451998, 244332656201, 938244497740, 3608640426930, 13899977105315, 53614228550220, 207061964668740, 800639722002163, 3099251007215286, 12009598156277090, 46582685655751645, 180850428684482360]

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

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