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A210780
Number of n X n 1..4 arrays with no element with value z exactly a city block distance of z from another element with value z
0
4, 176, 21379, 1115472, 98861559, 51104966068
OFFSET
1,1
COMMENTS
Diagonal of A210788
EXAMPLE
Some solutions for n=4
..4..4..1..2....2..4..1..2....3..1..4..4....2..1..3..1....2..1..3..3
..4..4..4..3....1..3..3..3....1..2..2..1....1..4..2..3....2..4..3..2
..2..1..3..1....4..2..3..1....3..1..3..4....3..1..2..4....4..1..4..2
..2..3..1..2....1..4..1..2....1..3..1..2....2..4..4..3....1..4..4..1
CROSSREFS
Sequence in context: A251695 A343610 A113254 * A127606 A041945 A300387
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 26 2012
STATUS
approved