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A242547
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Number of length n+3 0..6 arrays with no four elements in a row with pattern aabb (possibly a=b) and new values 0..6 introduced in 0..6 order
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1
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13, 43, 166, 712, 3339, 16968, 92360, 532175, 3210136, 20066475, 128848615, 843831762, 5605476437, 37615886287, 254237240993, 1726996739311, 11772647808288, 80450209850112, 550717024856208, 3774443585348691
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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) = 16*a(n-1) -95*a(n-2) +326*a(n-3) -998*a(n-4) +2268*a(n-5) -2953*a(n-6) +5002*a(n-7) -877*a(n-8) -8932*a(n-9) -5460*a(n-10) -46536*a(n-11) -36728*a(n-12) -4608*a(n-13) +43488*a(n-14) +180288*a(n-15) +260208*a(n-16) +254016*a(n-17) +207360*a(n-18) +103680*a(n-19) +20736*a(n-20)
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EXAMPLE
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Some solutions for n=4
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....0....1....1....1....1....1....1....0....1....1....1....1....1....0....1
..1....0....2....0....2....1....2....1....1....2....2....2....1....2....1....0
..2....1....1....2....3....2....1....0....2....3....0....2....2....0....0....2
..3....0....3....1....1....3....3....2....1....3....3....1....3....2....0....0
..1....2....3....1....4....2....0....1....0....0....3....0....0....2....2....3
..1....1....1....0....1....2....3....3....2....3....4....3....1....3....1....3
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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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