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A192997
Number of n X n symmetric 0..3 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..3 introduced in lower triangular row major order.
0
0, 1, 1, 6, 35, 675, 17727, 1019259, 90018848, 14424049245, 3763663443702, 1688522843271598, 1263001202178738616
OFFSET
1,4
EXAMPLE
Some solutions for 8 X 8 containing a 3
..0..0..0..0..2..2..1..1....0..0..0..0..0..0..0..0....0..0..0..0..2..2..2..2
..0..0..0..0..2..2..1..1....0..0..0..0..0..0..0..0....0..0..0..0..2..2..2..2
..0..0..1..1..1..1..3..3....0..0..0..0..0..0..0..0....0..0..1..1..1..1..1..1
..0..0..1..2..2..1..3..3....0..0..0..0..1..1..0..0....0..0..1..1..2..2..1..1
..2..2..1..2..2..1..2..2....0..0..0..1..1..1..2..2....2..2..1..2..2..2..3..3
..2..2..1..1..1..1..2..2....0..0..0..1..1..1..2..2....2..2..1..2..2..2..3..3
..1..1..3..3..2..2..2..2....0..0..0..0..2..2..3..3....2..2..1..1..3..3..3..3
..1..1..3..3..2..2..2..2....0..0..0..0..2..2..3..3....2..2..1..1..3..3..3..3
CROSSREFS
Sequence in context: A051337 A267224 A192996 * A152128 A115457 A192998
KEYWORD
nonn
AUTHOR
R. H. Hardin Jul 14 2011
STATUS
approved