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A270118
T(n,k)=Number of nXk 0..7 arrays with some element plus some horizontally or vertically adjacent neighbor totalling seven exactly once.
9
0, 8, 8, 112, 1344, 112, 1176, 100800, 100800, 1176, 10976, 6183744, 45440640, 6183744, 10976, 96040, 345422784, 16972694928, 16972694928, 345422784, 96040, 806736, 18272616768, 5795977666752, 38799000374400, 5795977666752
OFFSET
1,2
COMMENTS
Table starts
.......0..............8...................112........................1176
.......8...........1344................100800.....................6183744
.....112.........100800..............45440640.................16972694928
....1176........6183744...........16972694928..............38799000374400
...10976......345422784.........5795977666752...........81224231406183600
...96040....18272616768......1877723928063648.......161437591343857507392
..806736...932758314432....587581295287557312....310047482243688075320784
.6588344.46431146637120.179399371883007424176.581128015182716709115556736
LINKS
FORMULA
Empirical for column k:
k=1: a(n) = 14*a(n-1) -49*a(n-2)
k=2: a(n) = 86*a(n-1) -1849*a(n-2) for n>3
k=3: a(n) = 540*a(n-1) -75994*a(n-2) +835380*a(n-3) -2393209*a(n-4) for n>5
k=4: [order 6] for n>7
k=5: [order 14] for n>15
k=6: [order 26] for n>27
EXAMPLE
Some solutions for n=2 k=4
..0..0..1..6. .4..4..6..3. .4..0..1..1. .4..4..5..0. .0..0..0..5
..0..2..2..0. .0..1..5..4. .0..5..7..6. .0..7..5..1. .4..3..1..5
CROSSREFS
Sequence in context: A228071 A192386 A119932 * A270150 A065241 A255006
KEYWORD
nonn,tabl
AUTHOR
R. H. Hardin, Mar 11 2016
STATUS
approved