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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

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

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.

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 A196452 A227267

Adjacent sequences:  A000646 A000647 A000648 * A000650 A000651 A000652

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified November 1 05:10 EDT 2014. Contains 248888 sequences.