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.

A267726 Number of 3Xn arrays containing n copies of 0..3-1 with every element equal to at least one horizontal neighbor and the top left element equal to 0.

Table of values

n a(n)
1 0
2 2
3 2
4 30
5 58
6 588
7 2388
8 17456
9 102874
10 731154
11 5027962
12 36610288
13 266876496
14 1982397806
15 14796809106
16 111298650288
17 840466993090
18 6372988144620
19 48466708273020
20 369602842446350
21 2824995007935614
22 21637397279211678

List of values

[0, 2, 2, 30, 58, 588, 2388, 17456, 102874, 731154, 5027962, 36610288, 266876496, 1982397806, 14796809106, 111298650288, 840466993090, 6372988144620, 48466708273020, 369602842446350, 2824995007935614, 21637397279211678]

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

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