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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.

A154638 a(n) is the number of distinct reduced words of length n in the Coxeter group of "Apollonian reflections" in three dimensions.

Table of values

n a(n)
0 1
1 5
2 20
3 70
4 240
5 810
6 2730
7 9180
8 30870
9 103770
10 348840
11 1172610
12 3941730
13 13249980
14 44539470
15 149717970
16 503272440
17 1691734410
18 5686712730
19 19115706780
20 64256852070
21 215997400170
22 726068516040
23 2440656636210
24 8204191055730
25 27578131979580
26 92703029288670

List of values

[1, 5, 20, 70, 240, 810, 2730, 9180, 30870, 103770, 348840, 1172610, 3941730, 13249980, 44539470, 149717970, 503272440, 1691734410, 5686712730, 19115706780, 64256852070, 215997400170, 726068516040, 2440656636210, 8204191055730, 27578131979580, 92703029288670]

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

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