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.

A317759 Number of nX2 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

Table of values

n a(n)
1 2
2 6
3 10
4 20
5 42
6 89
7 190
8 407
9 873
10 1874
11 4024
12 8642
13 18561
14 39866
15 85627
16 183917
17 395034
18 848492
19 1822474
20 3914489
21 8407926
22 18059375
23 38789713
24 83316386
25 178955184
26 384377666
27 825604417
28 1773314930
29 3808901427
30 8181135701

List of values

[2, 6, 10, 20, 42, 89, 190, 407, 873, 1874, 4024, 8642, 18561, 39866, 85627, 183917, 395034, 848492, 1822474, 3914489, 8407926, 18059375, 38789713, 83316386, 178955184, 384377666, 825604417, 1773314930, 3808901427, 8181135701]

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

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