OFFSET
0,3
REFERENCES
S. J. Cyvin et al., Enumeration and classification of certain polygonal systems...: annelated catafusenes, J. Chem. Inform. Comput. Sci., 34 (1994), 1174-1180.
FORMULA
G.f.: (6 - 18x^3 - (1-x)*(1-2x)*f(x) - 3*(1+2x)*f(x^2) - 2*f(x^3))/(12x^3), where f(x) = sqrt(1 - 6x + 5x^2) (follows from eq. (26) in Cyvin et al.).
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Emeric Deutsch, Mar 14 2004
STATUS
approved