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A199640
Number of n X n 0..2 arrays with values 0..2 introduced in row major order and each element equal to one or two horizontal and vertical neighbors
0
0, 3, 112, 29229, 32177372, 176701683386, 4539946639286136
OFFSET
1,2
COMMENTS
Diagonal of A199647
EXAMPLE
Some solutions for n=3
..0..1..1....0..0..1....0..1..1....0..0..0....0..0..1....0..0..1....0..1..1
..0..1..0....1..0..1....0..0..1....0..1..2....0..1..1....0..2..1....0..2..1
..2..2..0....1..2..2....2..2..1....1..1..2....0..0..0....0..2..1....0..2..2
CROSSREFS
Sequence in context: A169996 A054330 A024043 * A221618 A300814 A075051
KEYWORD
nonn
AUTHOR
R. H. Hardin Nov 08 2011
STATUS
approved