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.

A375254 Number of distinct ways to erect n semicircles of distinct diameters in [n] on the number line from 1 to 2n using 2 colors where all semicircles of the same color are mutually noncrossing. Two ways are regarded the same if the number line is reversed or the colors are exchanged.

Table of values

n a(n)
1 0
2 0
3 0
4 6
5 4
6 0
7 0
8 60
9 186
10 0
11 0
12 1248
13 2590
14 0
15 0
16 22820
17 46384
18 0
19 0
20 365392
21 730456

List of values

[0, 0, 0, 6, 4, 0, 0, 60, 186, 0, 0, 1248, 2590, 0, 0, 22820, 46384, 0, 0, 365392, 730456]

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

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