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A255667
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Number of length n+7 0..3 arrays with at most two downsteps in every n consecutive neighbor pairs
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1
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65536, 262144, 1020000, 3083292, 7323894, 15269184, 29577432, 53275408, 90990131, 149141772, 236469626, 364664160, 549120490, 809830656, 1172434356, 1669450392, 2341713998, 3240048488, 4427203308, 5980094628, 7992389097
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = (1/39916800)*n^11 + (13/3628800)*n^10 + (1/4320)*n^9 + (211/24192)*n^8 + (1428221/1209600)*n^7 + (5660089/172800)*n^6 + (145503607/362880)*n^5 + (63892553/36288)*n^4 + (439312849/7200)*n^3 - (2124832139/12600)*n^2 + (67026258/385)*n - 159592 for n>5
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EXAMPLE
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Some solutions for n=1
..2....1....1....1....0....3....0....3....0....2....3....0....2....3....2....2
..0....3....2....1....2....0....1....3....1....1....3....2....3....2....3....0
..1....0....0....0....0....2....2....3....3....2....1....1....1....0....0....1
..1....2....0....3....2....1....3....1....2....2....2....1....1....2....1....3
..1....1....1....0....1....1....1....3....3....3....3....0....3....0....2....0
..1....3....2....1....3....3....0....2....3....0....1....3....0....1....3....1
..2....0....0....0....3....2....0....2....1....2....2....0....2....3....3....2
..1....3....0....0....3....1....0....0....1....0....0....1....1....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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