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A231019
Number of (n+3)X(n+3) 0..3 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 4, and upper left element zero
0
6, 242, 8374, 3160834, 584293702, 1576885946694, 2042677948725090, 36336036129055657778
OFFSET
1,1
COMMENTS
Diagonal of A231023
EXAMPLE
Some solutions for n=2
..x..0..x..1..x....x..0..x..2..x....x..0..x..3..x....x..0..x..0..x
..1..x..3..x..2....2..x..1..x..3....1..x..0..x..2....3..x..1..x..0
..x..2..x..3..x....x..3..x..0..x....x..2..x..1..x....x..2..x..1..x
..1..x..0..x..2....0..x..2..x..3....1..x..3..x..1....1..x..0..x..2
..x..3..x..1..x....x..1..x..2..x....x..0..x..2..x....x..3..x..3..x
CROSSREFS
Sequence in context: A080358 A233826 A156936 * A254009 A072228 A322559
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 03 2013
STATUS
approved