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A000649 Number of alkyls C_{n+15} H_{2n+10} (Phenan) with n carbon atoms.
(Formerly M3958 N1633)
1
1, 5, 30, 115, 425, 1396, 4440, 13470, 40000, 116140, 332827, 942435, 2647450, 7386925, 20511620, 56731383, 156451985, 430462915, 1182341890, 3243215495, 8887664047, 24338341165, 66616422775, 182276901760, 498657609720, 1364083988834 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

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

Table of n, a(n) for n=0..25.

G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; line 16 of Table I.

FORMULA

G.f.: A(x) = (r(x)^10+r(x^2)^5)/2, r(x) = A000598(x).

CROSSREFS

Cf. A000648.

Sequence in context: A062990 A018213 A047661 * A027173 A286973 A196452

Adjacent sequences:  A000646 A000647 A000648 * A000650 A000651 A000652

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified May 28 17:57 EDT 2017. Contains 287241 sequences.