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 A000552 Number of labeled rooted trees of height 3 with n nodes. (Formerly M5159 N2241) 2
 24, 300, 3360, 38850, 475776, 6231960, 87530400, 1316954430, 21173760960, 362670636900, 6596214691248, 126980000240730, 2579214238608000, 55118036257959600, 1235935135837111104, 29009023670878484598 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,1 REFERENCES 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). LINKS J. Riordan, Enumeration of trees by height and diameter, IBM J. Res. Dev. 4 (1960), 473-478. FORMULA E.g.f.: x*(exp(x*exp(x*exp(x)))-exp(x*exp(x))). - Vladeta Jovovic, Jan 29 2008 MAPLE 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[ 5159 ] := n -> count(ht(3), size=n)-count(ht(2), size=n): seq(M[ 5159 ](n), n=4..19); MATHEMATICA With[{nn=20}, Drop[CoefficientList[Series[x(Exp[x Exp[x Exp[x]]]- Exp[x Exp[x]]), {x, 0, nn}], x]Range[0, nn]!, 4]] (* Harvey P. Dale, Oct 01 2011 *) CROSSREFS Sequence in context: A014103 A321953 A206002 * A233876 A171742 A187851 Adjacent sequences:  A000549 A000550 A000551 * A000553 A000554 A000555 KEYWORD nonn,easy,nice AUTHOR EXTENSIONS More terms from Paul Zimmermann, Mar 15 1996 STATUS approved

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Last modified September 20 12:05 EDT 2021. Contains 347586 sequences. (Running on oeis4.)