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A284716
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Number of indecomposable permutations avoiding the pattern 2143.
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1
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1, 1, 3, 13, 63, 330, 1838, 10758, 65586, 413639, 2684469, 17852715, 121256457, 838843641, 5897455515, 42058344077, 303787163823, 2219452035639, 16383022072549, 122066094872139, 917245868993865, 6946236553301334, 52979616083094066, 406741647662973594
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OFFSET
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1,3
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LINKS
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FORMULA
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MATHEMATICA
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Rest[CoefficientList[Series[2*x - 1 + (1-x)^2 * (1 + 5*x - (1-9*x)^(3/4) * (1-x)^(1/4) * HypergeometricPFQ[{-1/4, 3/4}, {1}, 64*x/((x-1)*(1-9*x)^3)])/(6*x^2), {x, 0, 30}], x]] (* Vaclav Kotesovec, Apr 02 2017 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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