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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 (list; table; graph; refs; listen; history; text; internal format)
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

R. H. Hardin, Table of n, a(n) for n = 1..112

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

Adjacent sequences:  A270115 A270116 A270117 * A270119 A270120 A270121

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Mar 11 2016

STATUS

approved

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Last modified April 20 22:22 EDT 2019. Contains 322310 sequences. (Running on oeis4.)