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%I #16 May 17 2021 08:40:49
%S 2,4,5,7,8,9,12,13,14,16,18,19,22,23,26,27,29,31,33,35,38,39,42,43,46,
%T 50,52,54,60,65,68,72,77,89
%N List of numbers that are not the number of subtrees of some tree.
%C This is a finite list of 34 numbers.
%H É. Czabarka, L. Székely, and S. Wagner, <a href="https://doi.org/10.1016/j.dam.2009.07.004">The inverse problem for certain tree parameters</a>, Discrete Appl. Math., 157, 2009, 3314-3319, section 2.6.
%e 4 and 5 are in the sequence since the 2-vertex tree has 3 subtrees and an m-vertex tree (m>=3) has at least 6 subtrees.
%Y Cf. A344406 (caterpillars).
%K nonn,fini,full
%O 1,1
%A _Emeric Deutsch_, Oct 19 2011