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.

A185831 Half the number of nX5 binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Table of values

n a(n)
1 3
2 61
3 393
4 2398
5 15782
6 98975
7 649826
8 4143707
9 26679121
10 171597547
11 1102725806
12 7092378045
13 45590856963
14 293158517847
15 1884832244162
16 12118696565347
17 77918494954731
18 500981651046567
19 3221109348385647
20 20710370917938021

List of values

[3, 61, 393, 2398, 15782, 98975, 649826, 4143707, 26679121, 171597547, 1102725806, 7092378045, 45590856963, 293158517847, 1884832244162, 12118696565347, 77918494954731, 500981651046567, 3221109348385647, 20710370917938021]

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

Content is available under The OEIS End-User License Agreement.