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A000951 Number of forests with n nodes and height at most 4.
(Formerly M3026 N1226)
14
1, 3, 16, 125, 1296, 16087, 229384, 3687609, 66025360, 1303751051, 28151798544, 659841763957, 16681231615816, 452357366282655, 13095632549137576, 403040561722348913, 13138626717852194976, 452179922268565180819, 16381932383826669204640 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
REFERENCES
J. Riordan, Forests of labeled trees, J. Combin. Theory, 5 (1968), 90-103.
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
FORMULA
E.g.f.: exp(x*exp(x*exp(x*exp(x*exp(x))))).
MATHEMATICA
nn = 20; Range[0, nn]! CoefficientList[Series[Exp[x*Exp[x*Exp[x*Exp[x*Exp[x]]]]], {x, 0, nn}], x] (* T. D. Noe, Jun 21 2012 *)
CROSSREFS
Column k=4 of A210725. - Alois P. Heinz, Mar 15 2013
Sequence in context: A320254 A365627 A245012 * A000272 A246527 A159594
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Vladeta Jovovic, Apr 07 2001
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)