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.

A181140 The number of ways to color n balls in a row with 3 colors with no color runs having lengths greater than 4. This sequence is a special case of the general problem for coloring n balls in a row with p colors where each color has a given maximum run-length. In this example, the bounds are uniformly 4. It can be phrased in terms of tossing a p-faced die n times, requiring each face to have no runs longer than b.

Table of values

n a(n)
1 3
2 9
3 27
4 81
5 240
6 714
7 2124
8 6318
9 18792
10 55896
11 166260
12 494532
13 1470960
14 4375296
15 13014096
16 38709768
17 115140240
18 342478800
19 1018685808
20 3030029232
21 9012668160
22 26807724000
23 79738214400
24 237177271584
25 705471756288
26 2098389932544

List of values

[3, 9, 27, 81, 240, 714, 2124, 6318, 18792, 55896, 166260, 494532, 1470960, 4375296, 13014096, 38709768, 115140240, 342478800, 1018685808, 3030029232, 9012668160, 26807724000, 79738214400, 237177271584, 705471756288, 2098389932544]