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A140424 Number of n X n symmetric binary matrices with every 1 adjacent to some 0 horizontally or vertically. 0
1, 5, 33, 413, 10601, 528337, 51239609, 9724918961, 3609411455769, 2618162731691205, 3712251419364788297, 10289169690673968652093, 55746140612201223800718641, 590390724169460591054420145025 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..14.

CROSSREFS

Sequence in context: A087618 A322178 A134152 * A295090 A268296 A212296

Adjacent sequences:  A140421 A140422 A140423 * A140425 A140426 A140427

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 18 2008

STATUS

approved

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Last modified October 19 15:24 EDT 2021. Contains 348092 sequences. (Running on oeis4.)