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A191712 Number of n X n symmetric binary matrices with each 1 adjacent to no more than 1 E, S or NW neighboring 1 1
2, 6, 32, 299, 4522, 117199, 5102712, 374261742, 46287548443, 9645832171566, 3387747263942416, 2005204912303387717, 2000240978176372394879, 3362663470594685582801758, 9527114534581774926710620628 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..19

EXAMPLE

Some solutions for n=5

..1..0..0..1..1....0..0..1..0..0....0..1..0..1..0....0..1..0..0..1

..0..1..0..0..0....0..0..0..0..0....1..0..0..0..0....1..0..1..0..0

..0..0..0..0..0....1..0..0..0..0....0..0..1..0..0....0..1..0..1..0

..1..0..0..0..0....0..0..0..0..1....1..0..0..0..0....0..0..1..0..0

..1..0..0..0..1....0..0..0..1..1....0..0..0..0..0....1..0..0..0..1

CROSSREFS

Sequence in context: A133596 A088437 A191691 * A277475 A277484 A005736

Adjacent sequences:  A191709 A191710 A191711 * A191713 A191714 A191715

KEYWORD

nonn

AUTHOR

R. H. Hardin Jun 12 2011

STATUS

approved

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Last modified April 19 13:00 EDT 2021. Contains 343114 sequences. (Running on oeis4.)