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A301486
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Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
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1
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4, 18, 52, 148, 441, 1372, 4326, 13641, 42741, 133208, 414303, 1289070, 4015530, 12519594, 39044533, 121754095, 379591807, 1183290025, 3688511653, 11498007929, 35843459506, 111739411177, 348340800464, 1085925223300, 3385266114712
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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) = 8*a(n-1) -22*a(n-2) +15*a(n-3) +44*a(n-4) -86*a(n-5) +a(n-6) +87*a(n-7) -13*a(n-8) -39*a(n-9) +19*a(n-10) -56*a(n-11) -26*a(n-12) +38*a(n-13) +90*a(n-14) +118*a(n-15) -46*a(n-16) -18*a(n-17) -120*a(n-18) -6*a(n-19) -15*a(n-20) +26*a(n-21) +3*a(n-23) -a(n-24) for n>25
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EXAMPLE
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Some solutions for n=5
..0..1..0. .0..1..1. .0..1..1. .0..0..0. .0..1..0. .0..1..0. .0..0..1
..1..0..1. .1..0..0. .1..0..1. .1..1..0. .1..0..1. .1..1..1. .1..0..0
..0..1..0. .0..1..1. .0..1..0. .0..1..1. .1..0..0. .0..1..0. .1..1..0
..0..1..0. .1..0..1. .1..0..1. .0..0..1. .1..1..1. .0..0..1. .0..1..0
..0..1..0. .0..0..1. .1..0..0. .1..1..0. .0..0..1. .1..1..0. .1..0..1
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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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