A000645 Number of alkyls X^{II} C_n H_{2n+1} Y with n carbon atoms.

1, 2, 4, 10, 25, 64, 166, 437, 1157, 3087, 8276, 22287, 60230, 163284, 443820, 1209155, 3300890, 9027337, 24727437, 67829684, 186302693, 512301120, 1410237805, 3885803531, 10716571591, 29579231200, 81704634803, 225845362116

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

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

• G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; line 11 of Table I.
• G. Polya, Algebraische Berechnung der Anzahl der Isomeren einiger organischer Verbindungen, Zeit. f. Kristall., 93 (1936), 415-443; Table 1, line 11. (Annotated scanned copy)

Formula

G.f.: A(x) = A000598(x)/(1-A000642(x)).