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A005961 Number of acyclic disubstituted alkanes with n carbon atoms and identical substituents.
(Formerly M1447)
1

%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. 25-61 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976. [Annotated scanned copy] See p. 44.

%F G.f.: (1/(1-x*B(x)^2) + 1/(1-x*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

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Last modified January 29 01:39 EST 2020. Contains 331328 sequences. (Running on oeis4.)