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

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

Crossrefs

Sequence in context: A337869 A377827 A333736 * A061377 A183604 A228563

Adjacent sequences: A220701 A220702 A220703 * A220705 A220706 A220707

Keyword

nonn

Author

R. H. Hardin Dec 18 2012

Status

approved