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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, 1, 3, 13, 107, 1617, 44976, 2282408, 216083336, 37166744488, 11934907610044, 6974153590170208, 7595477025017870022, 15083748097547577433271, 55729708477784939752304144, 376141278066033748724918163244 (list; graph; refs; listen; history; text; internal format)
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: A073587 A337869 A333736 * A061377 A183604 A228563

Adjacent sequences:  A220701 A220702 A220703 * A220705 A220706 A220707

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 18 2012

STATUS

approved

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Last modified May 7 19:09 EDT 2021. Contains 343652 sequences. (Running on oeis4.)