

A230657


Number of n X n 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2x(i,j)


0



1, 3, 15, 123, 8613, 337977, 169006665, 40860127671, 131515599970167, 201844710508818147, 4141132208926170478473, 40464088148356899296269059
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OFFSET

1,2


COMMENTS



LINKS



EXAMPLE

Some solutions for n=5
..x..1..x..1..x....x..2..x..0..x....x..1..x..1..x....x..1..x..1..x
..1..x..1..x..1....0..x..1..x..2....1..x..0..x..1....1..x..2..x..1
..x..2..x..2..x....x..1..x..0..x....x..2..x..1..x....x..0..x..0..x
..0..x..1..x..0....2..x..2..x..1....2..x..1..x..2....2..x..0..x..2
..x..2..x..1..x....x..0..x..1..x....x..0..x..0..x....x..2..x..0..x


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



