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A196984
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Number of n X 3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,3,4,1,0 for x=0,1,2,3,4.
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1
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1, 3, 10, 25, 81, 242, 707, 2095, 6224, 18499, 54863, 162682, 482707, 1432377, 4249808, 12608401, 37408069, 110988820, 329298679, 977007545, 2898720410, 8600339717, 25516721819, 75706627806, 224617138645, 666426019913
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OFFSET
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1,2
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COMMENTS
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Every 0 is next to 0 2's, every 1 is next to 1 3's, every 2 is next to 2 4's, every 3 is next to 3 1's, every 4 is next to 4 0's.
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LINKS
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FORMULA
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Empirical: a(n) = a(n-1) +2*a(n-2) +6*a(n-3) +11*a(n-4) +14*a(n-5) +4*a(n-6) -4*a(n-7) -4*a(n-8) -a(n-9).
Empirical g.f.: x*(1 + 2*x + 5*x^2 + 3*x^3 + 7*x^4 + 4*x^5 - 3*x^6 - 5*x^7 - 2*x^8) / (1 - x - 2*x^2 - 6*x^3 - 11*x^4 - 14*x^5 - 4*x^6 + 4*x^7 + 4*x^8 + x^9). - Colin Barker, May 11 2018
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EXAMPLE
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Some solutions for n=4:
..0..0..0....0..0..1....1..3..1....1..0..0....0..0..1....0..1..0....0..0..0
..0..1..0....0..1..3....0..1..1....3..1..1....1..1..3....1..3..1....0..0..1
..1..3..1....0..1..1....0..1..3....1..1..3....3..1..1....0..0..0....0..1..3
..0..0..0....1..3..1....0..0..1....0..0..1....1..0..0....0..0..0....0..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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