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A209540
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Number of nX5 array permutations with every element making zero or one right-handed knight moves (out 2, right 1)
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1
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1, 8, 243, 6480, 103680, 2080800, 42166080, 833285376, 16312907520, 325995321600, 6453963360000, 127720737849600, 2530106562316032, 50139779258799360, 992798704350478080, 19665530247158611200, 389544838379796084480
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 19*a(n-1) +16*a(n-2) -119472*a(n-5) +2269968*a(n-6) +1911552*a(n-7) +606867456*a(n-10) -11530481664*a(n-11) -9709879296*a(n-12) +125275471872*a(n-15) -2380233965568*a(n-16) -2004407549952*a(n-17) -1099511627776*a(n-20) +20890720927744*a(n-21) +17592186044416*a(n-22) for n>24
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EXAMPLE
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Some solutions for n=4
..7.10..2..3.13....0..8..2..3.13....0.10..2..3.13....0.10.11.12..4
..5.15..0.17..9....5.15.14.17..9....5..6.14.17.18....5..6.14.17..9
..1.18.19..4.14....1.11.19..4..7....1.11.12..4..7....1..2..3.13..7
..6.16..8.11.12....6.16.10.18.12...15.16..8..9.19...15.16..8.18.19
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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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