A220546 Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly one horizontal, vertical or antidiagonal neighbor

1, 8, 224, 32173, 21668208, 69961268156, 1077372801893440, 79222784184855853978, 27809964251933826835780981, 46605836505704256743057461864323

Offset

1,2

Comments

Diagonal of A220553

Links

R. H. Hardin, Table of n, a(n) for n = 1..12

Example

Some solutions for n=3 0=self 2=n 3=ne 4=w 6=e 7=sw 8=s (reciprocal directions total 10)
..0..8..8....0..0..8....6..4..7....8..0..0....6..4..0....8..6..4....0..0..7
..8..2..2....0..7..2....8..3..0....2..8..8....0..7..0....2..8..0....0..3..0
..2..0..0....3..0..0....2..0..0....0..2..2....3..6..4....0..2..0....0..6..4

Crossrefs

Sequence in context: A230144 A013377 A214383 * A189445 A193786 A213799

Adjacent sequences: A220543 A220544 A220545 * A220547 A220548 A220549

Keyword

nonn

Author

R. H. Hardin Dec 15 2012

Status

approved