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A203094
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Number of nX1 0..3 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor
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2
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1, 4, 16, 50, 144, 422, 1268, 3823, 11472, 34350, 102896, 308419, 924532, 2771101, 8305373, 24892609, 74608516, 223618304, 670231838, 2008825312, 6020872062, 18045827096, 54087163859, 162110668160, 485879938474, 1456284886944
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OFFSET
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1,2
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COMMENTS
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Column 1 of A203101
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = 4*a(n-1) -6*a(n-2) +10*a(n-3) -5*a(n-4) +6*a(n-5) -a(n-6) +a(n-7)
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EXAMPLE
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Some solutions for n=5
..3....1....1....1....1....3....3....1....0....1....1....3....2....0....3....3
..3....1....1....2....2....3....3....1....2....1....1....3....2....2....3....3
..1....3....1....2....3....3....1....0....3....0....2....3....3....3....3....0
..3....3....2....1....3....3....3....0....3....0....2....3....3....3....2....1
..3....0....2....0....3....0....3....0....0....0....1....0....1....3....1....1
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CROSSREFS
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Sequence in context: A217951 A217950 A217949 * A121184 A203840 A089093
Adjacent sequences: A203091 A203092 A203093 * A203095 A203096 A203097
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin Dec 29 2011
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STATUS
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approved
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