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.

A203177 Number of nX4 0..2 arrays with every 1 immediately preceded by 0 to the left or above, no 0 immediately preceded by a 0, and every 2 immediately preceded by 0 1 to the left or above.

Table of values

n a(n)
1 2
2 4
3 17
4 59
5 205
6 724
7 2466
8 8948
9 30945
10 108083
11 382615
12 1333850
13 4692643
14 16441939
15 57654309
16 202490869
17 709321155
18 2489832932
19 8732839148
20 30624223891
21 107449317301
22 376820699674
23 1321873641658
24 4636665217896
25 16263018992261

List of values

[2, 4, 17, 59, 205, 724, 2466, 8948, 30945, 108083, 382615, 1333850, 4692643, 16441939, 57654309, 202490869, 709321155, 2489832932, 8732839148, 30624223891, 107449317301, 376820699674, 1321873641658, 4636665217896, 16263018992261]

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

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