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.

A202974 Number of n X 3 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 4
3 17
4 58
5 215
6 866
7 3507
8 14120
9 56921
10 229860
11 928443
12 3749720
13 15144167
14 61165438
15 247041429
16 997775144
17 4029911351
18 16276407572
19 65738788527
20 265512410122
21 1072378133103
22 4331228325504
23 17493399301365
24 70654095337584

List of values

[1, 4, 17, 58, 215, 866, 3507, 14120, 56921, 229860, 928443, 3749720, 15144167, 61165438, 247041429, 997775144, 4029911351, 16276407572, 65738788527, 265512410122, 1072378133103, 4331228325504, 17493399301365, 70654095337584]

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

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