A005955 Number of acyclic secondary alcohols with n carbon atoms. (Formerly M1453)

1, 2, 5, 14, 36, 98, 273, 768, 2197, 6360, 18584, 54780, 162672, 486154, 1461197, 4413988, 13393855, 40807290, 124783669, 382842018, 1178140280, 3635626680, 11247841224, 34880346840, 108402132544, 337576497920, 1053229358252, 3291813720292

Offset

3,2

References

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

Links

Table of n, a(n) for n=3..30.

R. C. Read, The Enumeration of Acyclic Chemical Compounds, pp. 25-61 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976. [Annotated scanned copy] See p. 44.

Formula

G.f. x*(B(x)-1)^2 where B(x) is the g.f. for A000625. - Sean A. Irvine, Nov 12 2016

Example

G.f. = x^3 + 2*x^4 + 5*x^5 + 14*x^6 + 36*x^7 + 98*x^8 + 273*x^9 + ...

Crossrefs

Cf. A000625.

Sequence in context: A102714 A087223 A363106 * A186903 A062197 A030016

Adjacent sequences: A005952 A005953 A005954 * A005956 A005957 A005958

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

More terms from Sean A. Irvine, Nov 12 2016

Status

approved