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.

A268888 Number of 3 X n binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

Table of values

n a(n)
1 0
2 20
3 84
4 501
5 2190
6 9996
7 42362
8 178400
9 732378
10 2974934
11 11933578
12 47466417
13 187325260
14 734639334
15 2865135348
16 11121381104
17 42989239524
18 165564387000
19 635557701344
20 2432620417837
21 9286486715514
22 35366757558512
23 134400104565934

List of values

[0, 20, 84, 501, 2190, 9996, 42362, 178400, 732378, 2974934, 11933578, 47466417, 187325260, 734639334, 2865135348, 11121381104, 42989239524, 165564387000, 635557701344, 2432620417837, 9286486715514, 35366757558512, 134400104565934]

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

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