A220616 - cp's OEIS frontend

A220616 Number of ways to reciprocally link elements of an n X 3 array either to themselves or to exactly one horizontal, diagonal and antidiagonal neighbor.

n	a(n)
1	3
2	21
3	125
4	765
5	4657
6	28373
7	172833
8	1052829
9	6413369
10	39067429
11	237981569
12	1449678893
13	8830805161
14	53793374581
15	327685538769
16	1996115937021
17	12159458878905
18	74070066514885
19	451202212873441
20	2748525099013581

[3, 21, 125, 765, 4657, 28373, 172833, 1052829, 6413369, 39067429, 237981569, 1449678893, 8830805161, 53793374581, 327685538769, 1996115937021, 12159458878905, 74070066514885, 451202212873441, 2748525099013581]

cp's OEIS Frontend

A220616 Number of ways to reciprocally link elements of an n X 3 array either to themselves or to exactly one horizontal, diagonal and antidiagonal neighbor.

Table of values

List of values