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A234762
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Number of (n+1) X (1+1) 0..3 arrays with 2 X 2 edge jumps all no more than +1 in one of the clockwise or counterclockwise directions but not both.
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1
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56, 240, 916, 3800, 14828, 60552, 239044, 967784, 3845148, 15493000, 61775668, 248247480, 991807292, 3979719864, 15917452772, 63817779896, 255404741740, 1023525137992, 4097640224516, 16416968389544, 65737110052316
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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) = a(n-1) + 14*a(n-2) - a(n-3) - 25*a(n-4) - 10*a(n-5).
Empirical g.f.: 4*x*(14 + 46*x - 27*x^2 - 105*x^3 - 39*x^4) / (1 - x - 14*x^2 + x^3 + 25*x^4 + 10*x^5). - Colin Barker, Oct 16 2018
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EXAMPLE
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Some solutions for n=5:
..0..0....1..1....1..2....3..0....1..2....1..2....2..2....2..1....2..3....3..2
..2..1....0..2....0..2....2..1....3..2....1..3....1..0....2..3....1..1....0..1
..2..3....1..2....1..1....3..3....1..2....1..2....1..2....2..1....0..2....2..2
..2..1....0..2....2..3....1..2....0..0....0..0....1..3....0..0....1..2....1..0
..3..1....1..2....1..1....0..3....1..2....2..1....1..2....2..1....3..2....1..2
..3..2....0..0....3..2....1..2....0..3....2..3....1..3....0..1....1..1....1..0
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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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