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A140421 Number of n X n symmetric binary matrices with every element adjacent to some zero horizontally or vertically. 0
3, 13, 160, 2817, 119145, 8890880, 1270451663, 347961207321, 183722336587008, 185316870246113925, 357804006282379850529, 1323503980097432239521792, 9379216327375443934023725295, 127291943357342220975708211213101 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..15.

CROSSREFS

Sequence in context: A224990 A065622 A246418 * A176315 A290758 A290769

Adjacent sequences:  A140418 A140419 A140420 * A140422 A140423 A140424

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 18 2008

STATUS

approved

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Last modified May 26 15:21 EDT 2019. Contains 323597 sequences. (Running on oeis4.)