login
A190626
Half the number of n X n symmetric binary matrices with no element equal to a strict majority of its diagonal and antidiagonal neighbors
0
1, 0, 2, 6, 42, 324, 4092, 76160, 2171670, 91674436, 5732036632, 535081395254, 74600276538996, 15457006345833026, 4764968523827845468, 2185341275223905432960, 1490580025901441886543202
OFFSET
1,3
EXAMPLE
Some solutions for n=4 with a(1,1)=0
..0..1..1..1....0..0..0..0....0..0..1..0....0..1..0..1....0..1..0..1
..1..1..0..0....0..1..1..0....0..1..1..0....1..1..0..0....1..1..0..1
..1..0..0..1....0..1..1..0....1..1..0..0....0..0..1..1....0..0..0..1
..1..0..1..1....0..0..0..0....0..0..0..1....1..0..1..0....1..1..1..1
CROSSREFS
Sequence in context: A127071 A353994 A151333 * A191975 A074015 A074021
KEYWORD
nonn
AUTHOR
R. H. Hardin May 14 2011
STATUS
approved