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A269767
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T(n,k)=Number of nXk 0..5 arrays with some element plus some horizontally or vertically adjacent neighbor totalling five exactly once.
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9
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0, 6, 6, 60, 480, 60, 450, 17520, 17520, 450, 3000, 524160, 2624640, 524160, 3000, 18750, 14288400, 326697720, 326697720, 14288400, 18750, 112500, 368958240, 37212131520, 170119348800, 37212131520, 368958240, 112500, 656250, 9195061680
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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.......480.........17520............524160..............14288400
....60.....17520.......2624640.........326697720...........37212131520
...450....524160.....326697720......170119348800........81208264293720
..3000..14288400...37212131520....81208264293720....162622227315688800
.18750.368958240.4022791852800.36821411380183680.309460647800786666280
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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) = 42*a(n-1) -441*a(n-2) for n>3
k=3: a(n) = 184*a(n-1) -9134*a(n-2) +61640*a(n-3) -112225*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
k=7: [order 64] for n>65
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EXAMPLE
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Some solutions for n=2 k=4
..0..5..3..4. .0..0..2..1. .3..5..1..2. .0..0..5..2. .3..1..2..4
..0..2..5..4. .1..2..4..4. .3..3..0..5. .0..2..2..0. .3..2..2..0
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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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