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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.

A305751 Number of achiral color patterns (set partitions) in a row or cycle of length n with 5 or fewer colors (subsets).

Table of values

n a(n)
0 1
1 1
2 2
3 3
4 7
5 12
6 30
7 55
8 141
9 266
10 688
11 1313
12 3407
13 6532
14 16970
15 32595
16 84721
17 162846
18 423348
19 813973
20 2116227
21 4069352
22 10580110
23 20345735
24 52898501
25 101726626
26 264488408
27 508629033
28 1322433847
29 2543136972
30 6612152850
31 12715668475

List of values

[1, 1, 2, 3, 7, 12, 30, 55, 141, 266, 688, 1313, 3407, 6532, 16970, 32595, 84721, 162846, 423348, 813973, 2116227, 4069352, 10580110, 20345735, 52898501, 101726626, 264488408, 508629033, 1322433847, 2543136972, 6612152850, 12715668475]

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

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