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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
OFFSET
2,1
CROSSREFS
Sequence in context: A224990 A065622 A246418 * A176315 A290758 A290769
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 18 2008
STATUS
approved