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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.

A175955 Number of ways to connect with nonintersecting chords n unlabeled points equally spaced on a circle such that the resulting configuration is not invariant w.r.t. rotation any angle < 2*Pi.

Table of values

n a(n)
1 1
2 0
3 1
4 1
5 4
6 6
7 18
8 36
9 92
10 209
11 527
12 1269
13 3218
14 8063
15 20701
16 53209
17 138634
18 362789
19 957857
20 2541735
21 6787960
22 18214250
23 49120018
24 133024306
25 361736098
26 987284765
27 2703991469
28 7429359867
29 20473889132
30 56579399002
31 156766505690

List of values

[1, 0, 1, 1, 4, 6, 18, 36, 92, 209, 527, 1269, 3218, 8063, 20701, 53209, 138634, 362789, 957857, 2541735, 6787960, 18214250, 49120018, 133024306, 361736098, 987284765, 2703991469, 7429359867, 20473889132, 56579399002, 156766505690]

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

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