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A269888
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T(n,k)=Number of nXk 0..5 arrays with some element plus some horizontally, diagonally, antidiagonally or vertically adjacent neighbor totalling five exactly once.
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8
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0, 6, 6, 60, 432, 60, 450, 11280, 11280, 450, 3000, 250992, 943488, 250992, 3000, 18750, 5125008, 68182800, 68182800, 5125008, 18750, 112500, 99482544, 4546948272, 16086672048, 4546948272, 99482544, 112500, 656250, 1867222224
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OFFSET
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1,2
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COMMENTS
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Table starts
......0..........6.............60................450...................3000
......6........432..........11280.............250992................5125008
.....60......11280.........943488...........68182800.............4546948272
....450.....250992.......68182800........16086672048..........3515869538472
...3000....5125008.....4546948272......3515869538472.......2524680110862912
..18750...99482544...288987039048....733651366146384....1733054018904626400
.112500.1867222224.17784013336560.148379658813705408.1153865935196746139616
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LINKS
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FORMULA
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Empirical for column k:
k=1: a(n) = 10*a(n-1) -25*a(n-2)
k=2: a(n) = 30*a(n-1) -197*a(n-2) -420*a(n-3) -196*a(n-4) for n>5
k=3: [order 10] for n>11
k=4: [order 28] for n>29
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EXAMPLE
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Some solutions for n=2 k=4
..3..2..0..2. .3..0..2..5. .3..0..4..5. .3..0..1..5. .0..4..2..3
..0..0..0..4. .2..0..1..1. .1..4..4..4. .1..0..0..1. .4..4..0..1
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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