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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.

A320643 Number of chiral pairs of color patterns (set partitions) in a cycle of length n using exactly 3 colors (subsets).

Table of values

n a(n)
1 0
2 0
3 0
4 0
5 0
6 4
7 12
8 44
9 137
10 408
11 1190
12 3416
13 9730
14 27560
15 78148
16 221250
17 627960
18 1784038
19 5081154
20 14496956
21 41455409
22 118764600
23 340919744
24 980315700
25 2823696150
26 8145853520
27 23533759241
28 68081765650
29 197206716570
30 571906256808
31 1660387879116
32 4825525985408
33 14037945170525
34 40875277302720
35 119122416494961
36 347440682773324
37 1014151818975190
38 2962391932326680
39 8659301777595196
40 25328461701728194

List of values

[0, 0, 0, 0, 0, 4, 12, 44, 137, 408, 1190, 3416, 9730, 27560, 78148, 221250, 627960, 1784038, 5081154, 14496956, 41455409, 118764600, 340919744, 980315700, 2823696150, 8145853520, 23533759241, 68081765650, 197206716570, 571906256808, 1660387879116, 4825525985408, 14037945170525, 40875277302720, 119122416494961, 347440682773324, 1014151818975190, 2962391932326680, 8659301777595196, 25328461701728194]

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

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