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.

A197050 Number of nX4 0..4 arrays with each element equal to the number its horizontal and vertical zero neighbors.

Table of values

n a(n)
1 3
2 6
3 18
4 42
5 108
6 274
7 692
8 1754
9 4442
10 11248
11 28488
12 72146
13 182712
14 462728
15 1171876
16 2967826
17 7516146
18 19034954
19 48206826
20 122085820
21 309187486
22 783030352
23 1983057390
24 5022176478
25 12718873752
26 32211084212
27 81575929322
28 206594481604

List of values

[3, 6, 18, 42, 108, 274, 692, 1754, 4442, 11248, 28488, 72146, 182712, 462728, 1171876, 2967826, 7516146, 19034954, 48206826, 122085820, 309187486, 783030352, 1983057390, 5022176478, 12718873752, 32211084212, 81575929322, 206594481604]