A045907 Catafusenes (see reference for precise definition).

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

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: A027631 A128620 A358438 * A254325 A351145 A034299

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