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URL: https://oeis.org/A190630

⇱ A190630 - OEIS

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A190630
Half the number of n X n symmetric binary matrices with no element equal to a strict majority of its knight-move neighbors.
0
1, 4, 6, 8, 63, 563, 10027, 209836, 6257561, 259705792
OFFSET
1,2
EXAMPLE
Some solutions for n=4 with a(1,1)=0
..0..1..0..0....0..0..1..0....0..0..1..1....0..1..0..0....0..0..1..1
..1..0..1..0....0..1..1..1....0..0..1..1....1..1..1..0....0..0..1..1
..0..1..1..1....1..1..1..0....1..1..0..0....0..1..1..1....1..1..1..0
..0..0..1..0....0..1..0..0....1..1..0..0....0..0..1..0....1..1..0..0
CROSSREFS
Sequence in context: A087271 A067797 A203633 * A390123 A013285 A013289
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 14 2011
STATUS
approved