A199241 - cp's OEIS frontend

A199241 Number of nX3 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or two horizontal or vertical neighbors.

n	a(n)
1	1
2	2
3	6
4	25
5	110
6	472
7	2080
8	9279
9	41704
10	187500
11	853012
12	3919309
13	18163022
14	84589504
15	395762792
16	1858908001
17	8762833946
18	41439737234
19	196527899276
20	934460643457
21	4453641597888
22	21271612632536
23	101795771318046

[1, 2, 6, 25, 110, 472, 2080, 9279, 41704, 187500, 853012, 3919309, 18163022, 84589504, 395762792, 1858908001, 8762833946, 41439737234, 196527899276, 934460643457, 4453641597888, 21271612632536, 101795771318046]

cp's OEIS Frontend

A199241 Number of nX3 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or two horizontal or vertical neighbors.

Table of values

List of values