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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
2, 6, 102, 1242, 98296, 4092246, 1088383766, 159130979900, 148986525600652, 76371552378548280, 250772217069255837720
OFFSET
1,1
COMMENTS
Diagonal of A230935
EXAMPLE
Some solutions for n=4
..x..0..x..2..x..2....x..0..x..2..x..2....x..0..x..0..x..2....x..0..x..0..x..2
..1..x..3..x..3..x....1..x..3..x..3..x....3..x..1..x..3..x....3..x..1..x..3..x
..x..2..x..0..x..0....x..2..x..0..x..2....x..2..x..0..x..0....x..2..x..2..x..2
..1..x..1..x..1..x....1..x..3..x..1..x....1..x..1..x..1..x....1..x..3..x..1..x
..x..0..x..2..x..0....x..2..x..2..x..0....x..2..x..0..x..2....x..0..x..0..x..0
..3..x..3..x..3..x....1..x..1..x..3..x....1..x..3..x..3..x....3..x..3..x..3..x
CROSSREFS
Sequence in context: A100704 A357084 A123257 * A054247 A278888 A099790
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 01 2013
STATUS
approved