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A220732
Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly two horizontal, diagonal and antidiagonal neighbors, without consecutive collinear links
0
1, 2, 22, 712, 127288, 94226589, 319803318494, 4830469921091502, 326643330141438534391
OFFSET
1,2
COMMENTS
Diagonal of A220738
EXAMPLE
Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10)
.00.67.47...00.69.47...00.69.47...00.69.47...00.67.47...00.00.00...00.79.00
.36.34.00...69.34.17...00.39.17...00.36.14...39.39.00...00.67.47...39.67.14
.00.00.00...00.13.00...00.36.14...00.00.00...00.16.14...36.34.00...36.14.00
CROSSREFS
Sequence in context: A308535 A318639 A354243 * A333796 A132568 A279802
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 18 2012
STATUS
approved