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A275403
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Number of 4_X_n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,0) or (-1,1) and new values introduced in order 0..2.
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1
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6, 31, 178, 1011, 5758, 32771, 186538, 1061795, 6043830, 34402035, 195819682, 1114623859, 6344543534, 36113737251, 205562777626, 1170082606339, 6660219918630, 37910596295955, 215790669012498, 1228300722808403
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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) = 3*a(n-1) + 11*a(n-2) + 25*a(n-3) + 2*a(n-4) - 24*a(n-5) for n>6.
Empirical g.f.: x*(6 + 13*x + 19*x^2 - 14*x^3 - 20*x^4 + 8*x^5) / (1 - 3*x - 11*x^2 - 25*x^3 - 2*x^4 + 24*x^5). - Colin Barker, Feb 04 2019
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EXAMPLE
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Some solutions for n=4:
..0..1..1..1. .0..0..0..1. .0..0..1..1. .0..1..1..2. .0..1..1..2
..0..0..0..1. .1..2..2..0. .2..2..0..0. .2..2..0..0. .2..0..1..1
..2..2..2..2. .1..1..1..2. .1..2..2..2. .1..2..2..0. .1..2..2..0
..1..1..1..2. .0..0..1..1. .1..1..1..1. .1..0..1..1. .0..1..2..2
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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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