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A000553
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Number of labeled rooted trees of height 4 with n nodes.
(Formerly M5378 N2335)
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1
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120, 2520, 43680, 757680, 13747104, 264181680, 5395040640, 117080049240, 2696387899920, 65774992411128, 1695845836077120, 46110625382246880, 1319345179723609920, 39640903618873667040, 1248193457738661143808
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OFFSET
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5,1
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REFERENCES
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N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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FORMULA
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E.g.f.: x*(exp(x*exp(x*exp(x*exp(x)))) - exp(x*exp(x*exp(x)))). - Vladeta Jovovic, Jan 29 2008
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MAPLE
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ht := proc(m) local i; [ T0, {seq(T.i=Prod(Z, Set(T.(i+1))), i=0..m-1), T.m=Z}, labeled ] end: M[ 5378 ] := n -> count(ht(4), size=n)-count(ht(3), size=n): seq(M[ 5378 ](n), n=5..19);
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MATHEMATICA
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egf = x*(Exp[x*Exp[x*Exp[x*Exp[x]]]] - Exp[x*Exp[x*Exp[x]]]); a[n_] := SeriesCoefficient[egf, {x, 0, n}]*n!; Table[a[n], {n, 5, 19}] (* Jean-François Alcover, Jan 17 2014, after Vladeta Jovovic *)
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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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