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A190625
Half the number of n X n symmetric binary matrices with no element equal to a strict majority of its horizontal and vertical neighbors
1
1, 1, 3, 9, 46, 338, 3788, 62929, 1549089, 56951770, 3109920701, 252393913470, 30471276950027, 5468189500564227, 1458879136021929400, 578685384553802577987, 341244992947305097698156
OFFSET
1,3
LINKS
EXAMPLE
Some solutions for n=4 with a(1,1)=0
..0..1..1..0....0..1..0..1....0..1..0..1....0..1..0..1....0..1..1..0
..1..0..0..1....1..0..1..0....1..0..0..1....1..1..0..0....1..0..0..1
..1..0..1..0....0..1..1..0....0..0..1..0....0..0..1..1....1..0..0..1
..0..1..0..1....1..0..0..1....1..1..0..1....1..0..1..0....0..1..1..0
CROSSREFS
Sequence in context: A180501 A188678 A107090 * A317079 A190627 A221986
KEYWORD
nonn
AUTHOR
R. H. Hardin May 14 2011
STATUS
approved