OFFSET
0,4
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. = V(z) + (U(z^2) + V(z)^2 - V(z^2)^2 + U(z^2)V(z)^2)/2 - V(z^2) + U(z^2)V(z), where U(z) = (1 - 3z - sqrt(1-6z + 5z^2))/(2z) and V(z) = (1 - z^2 - sqrt(1-6z^2+5z^4))/(2z(1-z)) (from eq. (54) of the Cyvin et al. paper). - Emeric Deutsch, May 02 2004
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Emeric Deutsch, May 02 2004
STATUS
approved