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A230927 Number of black-square subarrays of (n+2)X(n+2) 0..3 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero 0

%I

%S 2,6,102,1242,98296,4092246,1088383766,159130979900,148986525600652,

%T 76371552378548280,250772217069255837720

%N Number of black-square subarrays of (n+2)X(n+2) 0..3 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero

%C Diagonal of A230935

%e Some solutions for n=4

%e ..x..0..x..2..x..2....x..0..x..2..x..2....x..0..x..0..x..2....x..0..x..0..x..2

%e ..1..x..3..x..3..x....1..x..3..x..3..x....3..x..1..x..3..x....3..x..1..x..3..x

%e ..x..2..x..0..x..0....x..2..x..0..x..2....x..2..x..0..x..0....x..2..x..2..x..2

%e ..1..x..1..x..1..x....1..x..3..x..1..x....1..x..1..x..1..x....1..x..3..x..1..x

%e ..x..0..x..2..x..0....x..2..x..2..x..0....x..2..x..0..x..2....x..0..x..0..x..0

%e ..3..x..3..x..3..x....1..x..1..x..3..x....1..x..3..x..3..x....3..x..3..x..3..x

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 01 2013

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Last modified September 19 12:54 EDT 2020. Contains 337178 sequences. (Running on oeis4.)