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A187179
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Number of nontrivial compositions of differential operations and directional derivative of the n-th order on the space R^10.
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0
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7, 7, 8, 9, 11, 14, 19, 27, 40, 61, 95, 150, 239, 383, 616, 993, 1603, 2590, 4187, 6771, 10952, 17717, 28663, 46374, 75031, 121399, 196424, 317817, 514235, 832046, 1346275, 2178315, 3524584, 5702893, 9227471, 14930358, 24157823
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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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a(n) = 2*a(n-1)-a(n-3). G.f.: -x*(6*x^2+7*x-7) / ((x-1)*(x^2+x-1)). [Colin Barker, Dec 14 2012]
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MATHEMATICA
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LinearRecurrence[{2, 0, -1}, {7, 7, 8}, 40] (* Harvey P. Dale, Apr 29 2015 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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