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.

A228278 Number of n X 3 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically or nw-se diagonally.

Table of values

n a(n)
1 2
2 3
3 13
4 35
5 112
6 337
7 1034
8 3154
9 9637
10 29431
11 89895
12 274564
13 838609
14 2561372
15 7823242
16 23894643
17 72981777
18 222909351
19 680835436
20 2079486057
21 6351405998
22 19399196250
23 59251261117
24 180972030923
25 552745635451
26 1688259428536

List of values

[2, 3, 13, 35, 112, 337, 1034, 3154, 9637, 29431, 89895, 274564, 838609, 2561372, 7823242, 23894643, 72981777, 222909351, 680835436, 2079486057, 6351405998, 19399196250, 59251261117, 180972030923, 552745635451, 1688259428536]

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

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