A220557 Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly one horizontal or antidiagonal neighbor

1, 5, 64, 3966, 810778, 665748170, 1996515036228, 22849956206052338, 978504298175393645420, 158156973836014224403041023, 96121270674841350006417715266220

Offset

1,2

Comments

Diagonal of A220562

Links

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

Example

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

Crossrefs

Sequence in context: A061698 A351020 A238631 * A266962 A126955 A091105

Adjacent sequences: A220554 A220555 A220556 * A220558 A220559 A220560

Keyword

nonn

Author

R. H. Hardin Dec 16 2012

Status

approved