Search: id:A036506
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%I A036506
%S A036506 0,0,0,1,1,15,455,20230,1166886,82031250,6768679170,639276644655,
%T A036506 67876292150095,7992910154350121,1032869077119140625,145221924661653841820,
%U A036506 22060305511905816000860,3599313659344525384083060,627583654087024080928783956
%N A036506 Number of labeled 4-trees with n nodes.
%D A036506 F. Harary and E. Palmer, Graphical Enumeration, (1973), p. 30, Problem 
               1.13(b) with k=4.
%H A036506 T. D. Noe, <a href="b036506.txt">Table of n, a(n) for n=1..100</a>
%H A036506 <a href="Sindx_Tra.html#trees">Index entries for sequences related to 
               trees</a>
%F A036506 C(n,4)*(4*n-15)^(n-6).
%F A036506 Number of labeled k-trees on n nodes is binomial(n, k) * (k(n-k)+1)^(n-k-2).
%Y A036506 Cf. A000272 (labeled trees), A036361 (labeled 2-trees), A036362 (labeled 
               3-trees), A036506 (labeled 4-trees), A000055 (unlabeled trees), A054581 
               (unlabeled 2-trees).
%Y A036506 Sequence in context: A020285 A041423 A041420 this_sequence A005815 A120600 
               A129892
%Y A036506 Adjacent sequences: A036503 A036504 A036505 this_sequence A036507 A036508 
               A036509
%K A036506 nonn
%O A036506 1,6
%A A036506 N. J. A. Sloane (njas(AT)research.att.com).

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