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.

A202973 Number of n X 2 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

Table of values

n a(n)
1 1
2 2
3 4
4 7
5 14
6 31
7 69
8 155
9 354
10 814
11 1875
12 4326
13 9993
14 23095
15 53387
16 123430
17 285394
18 659913
19 1525942
20 3528541
21 8159347
22 18867623
23 43629460
24 100888804
25 233295503
26 539473228
27 1247479743
28 2884676711
29 6670537293
30 15424975984
31 35668774074

List of values

[1, 2, 4, 7, 14, 31, 69, 155, 354, 814, 1875, 4326, 9993, 23095, 53387, 123430, 285394, 659913, 1525942, 3528541, 8159347, 18867623, 43629460, 100888804, 233295503, 539473228, 1247479743, 2884676711, 6670537293, 15424975984, 35668774074]

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

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