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A290361
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Number of 7-leaf rooted trees with n levels.
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2
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0, 1, 15, 111, 518, 1789, 5026, 12166, 26328, 52221, 96613, 168861, 281502, 450905, 697984, 1048972, 1536256, 2199273, 3085467, 4251307, 5763366, 7699461, 10149854, 13218514, 17024440, 21703045, 27407601, 34310745, 42606046, 52509633, 64261884, 78129176
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OFFSET
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0,3
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LINKS
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B. A. Huberman and T. Hogg, Complexity and adaptation, Evolution, games and learning (Los Alamos, N.M., 1985). Phys. D 22 (1986), no. 1-3, 376-384.
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FORMULA
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G.f.: -(4*x^4+21*x^3+27*x^2+8*x+1)*x / (x-1)^7.
a(n) = (61*n^6+69*n^5+145*n^4+195*n^3+154*n^2+96*n)/6!.
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MAPLE
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a:= n-> (((((61*n+69)*n+145)*n+195)*n+154)*n+96)*n/6!:
seq(a(n), n=0..40);
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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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