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A220680 Number of ways to reciprocally link elements of an nX7 array either to themselves or to exactly two horizontal, vertical and antidiagonal neighbors, without consecutive collinear links 1
1, 441, 22000, 2316754, 215926776, 21051034046, 2045717834201, 198460804181024, 19267871745544463, 1870273847823355410, 181541549823743511322, 17622155633363587138681, 1710539337273283386055832 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 7 of A220681

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..107

EXAMPLE

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

.00.00.00.00.78.00.00...00.78.00.67.48.68.47...00.00.00.00.68.48.00

.68.48.00.38.27.78.00...38.27.38.00.27.23.78...00.00.68.48.26.24.78

.26.24.00.23.36.24.00...23.00.26.34.00.36.24...00.00.26.24.00.36.24

CROSSREFS

Sequence in context: A264262 A232003 A221248 * A189278 A151656 A264088

Adjacent sequences: A220677 A220678 A220679 * A220681 A220682 A220683

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 17 2012

STATUS

approved

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Last modified November 29 02:32 EST 2022. Contains 358421 sequences. (Running on oeis4.)