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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.

A174395 The number of different 4-colorings for the vertices of all triangulated planar polygons on a base with n vertices if the colors of two adjacent boundary vertices are fixed.

Table of values

n a(n)
3 0
4 2
5 10
6 40
7 140
8 462
9 1470
10 4580
11 14080
12 42922
13 130130
14 393120
15 1184820
16 3565382
17 10717990
18 32197660
19 96680360
20 290215842
21 870997050
22 2613690200
23 7842468700
24 23530202302
25 70596199310
26 211799782740
27 635421717840
28 1906309892762
29 5719019156770
30 17157236427280

List of values

[0, 2, 10, 40, 140, 462, 1470, 4580, 14080, 42922, 130130, 393120, 1184820, 3565382, 10717990, 32197660, 96680360, 290215842, 870997050, 2613690200, 7842468700, 23530202302, 70596199310, 211799782740, 635421717840, 1906309892762, 5719019156770, 17157236427280]

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

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