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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
1, 8, 224, 32173, 21668208, 69961268156, 1077372801893440, 79222784184855853978, 27809964251933826835780981, 46605836505704256743057461864323 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 17 17:59 EST 2020. Contains 331999 sequences. (Running on oeis4.)