A230735 Number of (n+3)X(n+3) 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero.
2, 66, 2106, 320970, 43853402, 36695929036, 26681634560690, 121531720205091748, 479398570293769095556, 11869733818244916838154264
Offset: 1
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Some solutions for n=3 ..x..0..x..0..x..1....x..0..x..1..x..0....x..0..x..2..x..2....x..0..x..2..x..2 ..2..x..1..x..2..x....1..x..2..x..1..x....2..x..1..x..0..x....2..x..1..x..0..x ..x..2..x..1..x..1....x..2..x..1..x..2....x..2..x..0..x..1....x..1..x..0..x..1 ..0..x..1..x..2..x....1..x..0..x..0..x....0..x..2..x..2..x....2..x..2..x..2..x ..x..1..x..0..x..1....x..0..x..1..x..2....x..1..x..2..x..1....x..0..x..2..x..1 ..0..x..2..x..0..x....2..x..2..x..0..x....0..x..1..x..0..x....2..x..1..x..0..x
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