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A192998
Number of n X n symmetric 0..4 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..4 introduced in lower triangular row major order.
0
0, 1, 1, 6, 35, 696, 19367, 1427148, 166223667, 40685390643, 16395208634778
OFFSET
1,4
EXAMPLE
Some solutions for 8 X 8 containing a 4
..0..0..0..2..2..3..3..3....0..0..0..2..2..2..4..4....0..0..0..0..2..2..1..1
..0..0..0..2..2..3..3..3....0..0..0..2..2..2..4..4....0..0..0..0..2..2..1..1
..0..0..1..1..2..2..0..0....0..0..1..1..2..2..1..1....0..0..1..1..0..0..4..4
..2..2..1..1..1..2..0..0....2..2..1..1..2..2..1..1....0..0..1..1..0..0..4..4
..2..2..2..1..1..2..2..2....2..2..2..2..2..3..3..1....2..2..0..0..1..1..1..1
..3..3..2..2..2..2..2..2....2..2..2..2..3..3..3..1....2..2..0..0..1..3..3..1
..3..3..0..0..2..2..4..4....4..4..1..1..3..3..3..1....1..1..4..4..1..3..3..1
..3..3..0..0..2..2..4..4....4..4..1..1..1..1..1..1....1..1..4..4..1..1..1..1
CROSSREFS
Sequence in context: A192997 A152128 A115457 * A192999 A193000 A193001
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 14 2011
STATUS
approved