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A234720
Number of (n+1) X (n+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7 (constant-stress 1 X 1 tilings).
0
240, 3976, 33560, 357208, 2557656, 23137720, 157274648, 1310504248, 8760624600
OFFSET
1,1
EXAMPLE
Some solutions for n=3:
1 6 3 7 4 0 6 0 2 5 0 3 5 1 7 2 0 5 3 3
3 1 5 2 1 4 3 4 6 2 4 0 1 4 3 5 4 2 7 0
0 5 2 6 5 1 7 1 4 7 2 5 5 1 7 2 1 6 4 4
2 0 4 1 1 4 3 4 7 3 5 1 2 5 4 6 4 2 7 0
CROSSREFS
Diagonal of A234728.
Sequence in context: A005950 A279746 A004536 * A249533 A324070 A145094
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 30 2013
STATUS
approved