login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A052514 Number of labeled trees of height at most 4. 3
0, 1, 2, 9, 64, 625, 7056, 89929, 1284032, 20351601, 354648160, 6736612201, 138472331328, 3061103815081, 72391319923664, 1823032999274985, 48692068509655936, 1374488205290880481, 40877130077266074048 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..18.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 60

FORMULA

E.g.f.: x*exp(x*exp(x*exp(x*exp(x))))

MAPLE

spec := [S, {T2=Prod(Z, Set(T3)), S=Prod(Z, Set(T1)), T4=Z, T3=Prod(Z, Set(T4)), T1=Prod(Z, Set(T2))}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);

MATHEMATICA

With[{nn=20}, CoefficientList[Series[x*Exp[x*Exp[x*Exp[x*Exp[x]]]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jul 23 2018 *)

CROSSREFS

Sequence in context: A269770 A269649 A128577 * A274395 A036776 A036777

Adjacent sequences:  A052511 A052512 A052513 * A052515 A052516 A052517

KEYWORD

easy,nonn

AUTHOR

encyclopedia(AT)pommard.inria.fr, Jan 25 2000

EXTENSIONS

Added "at most" in the title; by Stanislav Sykora, May 12 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 16 08:26 EST 2019. Contains 320159 sequences. (Running on oeis4.)