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A202981
Number of n X n 0..2 arrays with every nonzero element less than or equal to some NW, E or S neighbor
0
1, 9, 1233, 595202, 2075667829, 54374200726981, 9811910575029966643, 12034608427204532840940835, 102201977619119405092991507364893, 6015924965468985859548914234181730364514
OFFSET
1,2
COMMENTS
Diagonal of A202988
EXAMPLE
Some solutions for n=3
..1..2..2....0..1..2....1..0..0....2..2..2....2..1..0....1..1..0....0..2..0
..1..2..2....2..2..2....2..2..1....1..1..2....2..2..0....1..1..1....2..2..2
..1..1..1....2..2..2....0..2..2....1..1..1....0..0..2....1..1..1....1..1..0
CROSSREFS
Sequence in context: A365595 A266602 A084149 * A276823 A020261 A266864
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 26 2011
STATUS
approved