A000641 Number of paraffins C_n H_{2n-1} X_3 with n carbon atoms. (Formerly M1456 N0575)

0, 1, 2, 5, 14, 39, 109, 312, 890, 2552, 7325, 21047, 60465, 173750, 499068, 1433071, 4113105, 11799780, 33834367, 96968462, 277771344, 795310628, 2276055442, 6510786627, 18616389094, 53207964655, 152014267327, 434136228215

Offset

0,3

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..27.

G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; line 7 of Table I.

G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; Table I, line 7. (Annotated scanned copy)

G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; Table I, line 7. (Annotated scanned copy)

Formula

G.f.: A(x) = ((x*r)/6)*( 1/(1-x*R)^3 + 3/((1-x*R)*(1-x^2*R2)) + 2/(1-x^3*R3)); r = A000598(x), R=A000642(x)/x, Ri=R(x^i).

Crossrefs

Sequence in context: A142586 A202207 A132834 * A026135 A201778 A367655

Adjacent sequences: A000638 A000639 A000640 * A000642 A000643 A000644

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved