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.

A301842 Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.

Table of values

n a(n)
1 2
2 8
3 25
4 81
5 263
6 855
7 2778
8 9027
9 29333
10 95316
11 309725
12 1006437
13 3270370
14 10626915
15 34531665
16 112209036
17 364618033
18 1184809305
19 3849982618
20 12510339087
21 40651763813
22 132096011916
23 429239834325
24 1394794836717
25 4532320816850

List of values

[2, 8, 25, 81, 263, 855, 2778, 9027, 29333, 95316, 309725, 1006437, 3270370, 10626915, 34531665, 112209036, 364618033, 1184809305, 3849982618, 12510339087, 40651763813, 132096011916, 429239834325, 1394794836717, 4532320816850]