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A316416
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Number of nX4 0..1 arrays with every element unequal to 0, 1, 2, 5, 6 or 8 king-move adjacent elements, with upper left element zero.
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1
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8, 9, 27, 93, 287, 1009, 3496, 11962, 41160, 142076, 489828, 1688040, 5819002, 20061466, 69159010, 238412640, 821894454, 2833376300, 9767673768, 33672696882, 116082018872, 400176917418, 1379555120878, 4755827350460, 16395063986690
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 2*a(n-1) +6*a(n-2) -a(n-3) -a(n-4) -17*a(n-5) -40*a(n-6) +16*a(n-7) +42*a(n-8) +13*a(n-9) +39*a(n-10) +7*a(n-11) -47*a(n-12) -20*a(n-13) -4*a(n-14) -12*a(n-15) +10*a(n-16) +20*a(n-17) -4*a(n-18) -8*a(n-19) for n>23
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EXAMPLE
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Some solutions for n=5
..0..1..0..0. .0..0..1..1. .0..0..0..0. .0..0..0..0. .0..1..1..0
..0..0..0..1. .0..1..0..1. .1..0..0..0. .0..0..0..0. .0..1..1..0
..0..0..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..0. .0..0..0..0
..1..0..0..0. .0..0..0..0. .1..0..0..0. .0..0..1..0. .0..0..0..0
..0..0..0..0. .0..1..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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