%I M1447
%S 1,2,5,13,37,108,325,993,3070,9564,29979,94392,298311,945592,3005021,
%T 9570559,30539044,97611676,312462096,1001554565,3214232129,
%U 10326580526,33210135104,106901289420,344398593149,1110395171502,3582666470285,11567123373968
%N Number of acyclic disubstituted alkanes with n carbon atoms and identical substituents.
%C Acyclic alkanes of the form C_nH_mX2.  _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. 2561 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976. [Annotated scanned copy] See p. 44.
%F G.f.: (1/(1x*B(x)^2) + 1/(1x*B(x^2))/2 where B(x) is the g.f. for A000625.  _Sean A. Irvine_, Nov 12 2016
%Y Cf. A005960.
%K nonn
%O 1,2
%A _N. J. A. Sloane_
%E More terms and title improved by _Sean A. Irvine_, Nov 12 2016
