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A140963
Half the number of n X n symmetric binary matrices with each 1 adjacent to an even number of other 1's.
1
1, 3, 14, 99, 1082, 17997, 460186, 17967189, 1075650798, 98475760770, 13808877966564, 2962829880373443, 973285891955586078, 489313659027753121941, 376571597820325396861232
OFFSET
1,2
LINKS
R. H. Hardin, Jul 27 2008, Table of n, a(n) for n = 1..21
CROSSREFS
Sequence in context: A336947 A038051 A132008 * A284759 A284760 A076015
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 27 2008
STATUS
approved