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A000636 Number of paraffins C_n H_{2n} X_2 with n carbon atoms.
(Formerly M1185 N0457)
1
1, 2, 4, 9, 21, 52, 129, 332, 859, 2261, 5983, 15976, 42836, 115469, 312246, 847241, 2304522, 6283327, 17164401, 46972357, 128741107, 353345434, 970999198, 2671347292, 7356752678, 20279171785, 55948407837, 154479213626, 426845422807, 1180229767202 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
REFERENCES
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
H. R. Henze and C. M. Blair, The number of structural isomers of the more important types of aliphatic compounds, J. Amer. Chem. Soc., 56 (1) (1934), 157-157.
H. R. Henze and C. M. Blair, The number of structural isomers of the more important types of aliphatic compounds, J. Amer. Chem. Soc., 56 (1) (1934), 157-157. (Annotated scanned copy)
G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; line 4 of Table I.
G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; Table I, line 2. (Annotated scanned copy)
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. 28.
FORMULA
G.f.: (1/2) * (1/(1-x*R(x)) + (1+x*R(x)) / (1-x^2*R(x^2))) where R(x) is the g.f. for A000642 [From Polya paper]. - Sean A. Irvine, Oct 04 2016
CROSSREFS
Sequence in context: A027057 A333105 A148071 * A204352 A195980 A136753
KEYWORD
nonn,easy,nice
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Oct 04 2016
STATUS
approved

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Last modified March 19 03:21 EDT 2024. Contains 370952 sequences. (Running on oeis4.)