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A275179
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Number of n X 4 0..2 arrays with no element equal to any value at offset (-2,-1) (-1,0) or (-1,1) and new values introduced in order 0..2.
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1
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14, 64, 89, 141, 353, 914, 2386, 6228, 16249, 42451, 111108, 291065, 762378, 1995896, 5223852, 13673069, 35794346, 93714905, 245360591, 642367172, 1681704625, 4402670689, 11526266952, 30176270194, 79002891883, 206832552922
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 8*a(n-1) - 28*a(n-2) + 57*a(n-3) - 70*a(n-4) + 47*a(n-5) - 12*a(n-6) - a(n-7) - 2*a(n-8) + a(n-9) for n>12.
Empirical g.f.: x*(14 - 48*x - 31*x^2 + 423*x^3 - 951*x^4 + 787*x^5 + 311*x^6 - 920*x^7 + 378*x^8 + 125*x^9 + 29*x^10 - 32*x^11) / ((1 - 3*x + x^2)*(1 - 5*x + 12*x^2 - 16*x^3 + 10*x^4 - x^5 - x^6 - x^7)). - Colin Barker, Feb 01 2019
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EXAMPLE
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Some solutions for n=4:
..0..1..1..1. .0..1..1..2. .0..0..0..1. .0..0..1..2. .0..1..1..2
..2..0..0..0. .2..2..0..1. .1..2..2..0. .2..2..0..1. .2..2..0..0
..1..2..2..2. .0..1..2..2. .0..1..1..2. .1..1..2..2. .0..1..2..2
..0..1..1..1. .2..0..1..1. .2..0..0..1. .2..0..1..1. .2..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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