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A000251 Number of trees of diameter 6.
(Formerly M2887 N1158)
2

%I M2887 N1158

%S 1,3,11,29,74,167,367,755,1515,2931,5551,10263,18677,33409,59024,

%T 102984,177915,304458,516939,871180,1458882,2428548,4021670,6627515,

%U 10874462,17770474,28932739,46943967,75925797,122433291,196879385,315759282,505168033,806290796,1284034606,2040485004,3235965074,5121801962,8091411114,12759606939,20085832527,31565046053,49523414558,77575278933,121329065354,189475663960,295465391518,460087656595,715436020515,1110994054004

%N Number of trees of diameter 6.

%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H J. Riordan, <a href="http://dx.doi.org/10.1147/rd.45.0473">Enumeration of trees by height and diameter</a>, IBM J. Res. Dev. 4 (1960), 473-478.

%H <a href="/index/Tra#trees">Index entries for sequences related to trees</a>

%Y Cf. A034853, A000550 (diameter 7).

%K nonn

%O 7,2

%A _N. J. A. Sloane_

%E More terms from _Sean A. Irvine_, Nov 21 2010

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Last modified May 25 17:53 EDT 2020. Contains 334595 sequences. (Running on oeis4.)