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A191274
Number of n X n symmetric binary matrices with each 1 adjacent to exactly 2 diagonally or antidiagonally neighboring 1s
1
1, 1, 2, 3, 8, 35, 208, 1147, 10098, 106904, 1615656, 31267328, 833655362, 29769092579, 1422289731681, 88322500448612, 7254260374065120, 782791757341222545, 111845565903325791194, 21080332457396845047136
OFFSET
1,3
LINKS
EXAMPLE
All solutions for n=4
..0..0..0..0....0..1..0..0....0..0..0..0
..0..0..1..0....1..0..1..0....0..0..0..0
..0..1..0..1....0..1..0..0....0..0..0..0
..0..0..1..0....0..0..0..0....0..0..0..0
CROSSREFS
Sequence in context: A005370 A112866 A041657 * A041789 A174899 A201370
KEYWORD
nonn
AUTHOR
R. H. Hardin May 29 2011
STATUS
approved