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Number of carbon trees with n carbon atoms.
(Formerly M1962)
0

%I M1962 #22 Feb 09 2017 06:19:26

%S 1,1,2,4,10,22,60,158,439,1229,3525,10178,29802,87862,261204,781198,

%T 2350249,7105081,21577415,65787902,201313311,618040002,1903102730,

%U 5876174472,18189503139,56435742554,175477142565,546703920430,1706433403626

%N Number of carbon trees with n carbon atoms.

%C Table II in the Read article is missing a(4)=4 and thereafter all entries in the table are off by one position. - _Sean A. Irvine_, Nov 12 2016

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

%H R. C. Read, <a href="/A000598/a000598.pdf">The Enumeration of Acyclic Chemical Compounds</a>, pp. 25-61 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976. [Annotated scanned copy] See p. 44.

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

%F G.f.: x * (B(x)^4 + 3*B(x^2)^2 + 8*B(x)*B(x^3)) / 12 where B(x) is the g.f. for A000625. - _Sean A. Irvine_, Nov 12 2016

%K nonn

%O 1,3

%A _N. J. A. Sloane_

%E a(4) inserted and more terms from _Sean A. Irvine_, Nov 12 2016