A000649 Number of alkyls C_{n+15} H_{2n+10} (Phenan) with n carbon atoms. (Formerly M3958 N1633)

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

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.

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

Formula

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

Crossrefs

Cf. A000648.

Sequence in context: A018213 A359975 A047661 * A027173 A286973 A196452

Adjacent sequences: A000646 A000647 A000648 * A000650 A000651 A000652

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved