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Search: id:A140421
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A140421 Number of n X n symmetric binary matrices with every element adjacent to some zero horizontally or vertically. +0
1
3, 13, 160, 2817, 119145, 8890880, 1270451663, 347961207321, 183722336587008, 185316870246113925, 357804006282379850529, 1323503980097432239521792, 9379216327375443934023725295, 127291943357342220975708211213101 (list; graph; listen)
OFFSET

2,1
CROSSREFS

Sequence in context: A108554 A014376 A065622 this_sequence A114317 A081299 A117808

Adjacent sequences: A140418 A140419 A140420 this_sequence A140422 A140423 A140424

KEYWORD

nonn

AUTHOR

Ron Hardin (rhhardin(AT)att.net), Jun 18 2008

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.

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