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A193310
Number of n X n symmetric 0..4 arrays with no element equal to any horizontal or vertical neighbor, containing at least one 4 and with new values 0..4 introduced in lower triangular row major order
1
0, 0, 9, 4369, 3042328, 5698808287, 33317286304173, 628998137157508637, 38569165397999629055394, 7686739047191692875345982285, 4979433998253869605167632947630885
OFFSET
1,3
LINKS
EXAMPLE
Some solutions for 4X4
..0..1..3..2....0..1..2..3....0..1..0..4....0..1..2..4....0..1..2..0
..1..2..0..1....1..0..3..2....1..2..3..0....1..2..0..1....1..0..1..2
..3..0..4..0....2..3..2..3....0..3..2..1....2..0..3..4....2..1..3..4
..2..1..0..2....3..2..3..4....4..0..1..3....4..1..4..0....0..2..4..2
CROSSREFS
Sequence in context: A036516 A024126 A163018 * A216421 A323337 A167064
KEYWORD
nonn
AUTHOR
R. H. Hardin Jul 22 2011
STATUS
approved