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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.

A103293 Number of ways to color n regions arranged in a line such that consecutive regions do not have the same color.

Table of values

n a(n)
0 1
1 1
2 1
3 2
4 4
5 11
6 32
7 117
8 468
9 2152
10 10743
11 58487
12 340390
13 2110219
14 13830235
15 95475556
16 691543094
17 5240285139
18 41432986588
19 341040317063
20 2916376237350
21 25862097486758
22 237434959191057
23 2253358057283035
24 22076003468637450
25 222979436690612445

List of values

[1, 1, 1, 2, 4, 11, 32, 117, 468, 2152, 10743, 58487, 340390, 2110219, 13830235, 95475556, 691543094, 5240285139, 41432986588, 341040317063, 2916376237350, 25862097486758, 237434959191057, 2253358057283035, 22076003468637450, 222979436690612445]

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

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