A220704 - OEIS

A220704

Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly two horizontal and antidiagonal neighbors, without consecutive collinear links

1, 1, 3, 13, 107, 1617, 44976, 2282408, 216083336, 37166744488, 11934907610044, 6974153590170208, 7595477025017870022, 15083748097547577433271, 55729708477784939752304144, 376141278066033748724918163244

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OFFSET

1,3

COMMENTS

Diagonal of A220708

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..18

EXAMPLE

All solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10)

.00.00.00...00.67.47...00.00.00

.00.00.00...36.34.00...00.67.47

.00.00.00...00.00.00...36.34.00