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A183353
One quarter the number of n X n 1..4 arrays with no two neighbors of any element equal to each other
0
1, 36, 432, 3600, 24192, 147456, 829440, 4460544, 23003136, 115605504, 566231040, 2727346176, 12910067712
OFFSET
1,2
COMMENTS
Diagonal of A183362
EXAMPLE
Some solutions for 5X5 with a(1,1)=1
..1..3..2..2..4....1..2..3..1..4....1..3..3..2..2....1..1..3..4..2
..2..4..1..3..4....1..4..3..2..4....1..2..4..4..3....3..2..2..4..1
..3..4..1..3..2....3..4..1..2..3....3..2..1..1..3....4..4..1..3..3
..1..2..2..4..1....2..2..1..4..3....4..4..3..2..4....2..3..1..2..2
..4..3..3..4..1....1..3..3..4..1....1..1..3..2..1....1..3..4..4..1
CROSSREFS
Sequence in context: A027782 A179099 A181685 * A178690 A370225 A222781
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 04 2011
STATUS
approved