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A045907 Catafusenes (see reference for precise definition). 0
0, 1, 1, 4, 6, 15, 25, 57, 103, 223, 417, 898, 1722, 3707, 7211, 15620, 30724, 66939, 132729, 290916, 580680, 1279281, 2567397, 5682009, 11456481, 25454265, 51528969, 114880470, 233380592, 521860455, 1063460261, 2384247105 (list; graph; refs; listen; history; text; internal format)
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.

LINKS

Table of n, a(n) for n=0..31.

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

Sequence in context: A109731 A027631 A128620 * A254325 A034299 A007135

Adjacent sequences:  A045904 A045905 A045906 * A045908 A045909 A045910

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Emeric Deutsch, May 02 2004

STATUS

approved

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Last modified June 2 16:52 EDT 2020. Contains 334787 sequences. (Running on oeis4.)