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A281931
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Number of nX3 0..1 arrays with no element equal to more than four of its king-move neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
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1
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0, 1, 20, 312, 3573, 31410, 252630, 1925590, 14065552, 99735307, 691339079, 4705890596, 31562889402, 209107683151, 1370993621183, 8908621893421, 57438444240641, 367809712917088, 2341050421702590, 14819986285211521
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OFFSET
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1,3
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 15*a(n-1) -63*a(n-2) +23*a(n-3) +3*a(n-4) +1161*a(n-5) +208*a(n-6) -2013*a(n-7) -8424*a(n-8) -6999*a(n-9) +7797*a(n-10) +25689*a(n-11) +44356*a(n-12) +27282*a(n-13) -498*a(n-14) -60721*a(n-15) -115722*a(n-16) -113223*a(n-17) -120471*a(n-18) -77700*a(n-19) -35280*a(n-20) -21952*a(n-21) for n>26
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EXAMPLE
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Some solutions for n=4
..0..0..0. .0..1..1. .0..1..1. .0..1..1. .0..0..1. .0..0..1. .0..1..1
..0..0..0. .0..0..1. .1..0..0. .0..0..1. .1..0..0. .1..1..0. .1..0..0
..1..1..1. .0..0..0. .0..0..0. .0..0..0. .1..0..0. .1..1..1. .0..0..0
..0..0..1. .1..1..0. .1..1..0. .0..1..1. .0..1..0. .0..1..1. .0..1..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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