A220628 - cp's OEIS frontend

A220628 Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly two horizontal or antidiagonal neighbors.

n	a(n)
1	1
2	1
3	3
4	37
5	1481
6	183961
7	72097810
8	91163971015
9	374610359478958
10	4999831941923800805
11	216409223358914018252290
12	30357148112130816204187346595
13	13800400036239294148735727438211949

[1, 1, 3, 37, 1481, 183961, 72097810, 91163971015, 374610359478958, 4999831941923800805, 216409223358914018252290, 30357148112130816204187346595, 13800400036239294148735727438211949]

cp's OEIS Frontend

A220628 Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly two horizontal or antidiagonal neighbors.

Table of values

List of values