A044044 Catafusenes (see reference for precise definition).

0, 1, 2, 2, 6, 10, 19, 36, 72, 135, 274, 543, 1084, 2219, 4438, 9280, 18570, 39587, 79169, 171369, 342738, 751221, 1502472, 3328218, 6656421, 14878455, 29756910, 67030734, 134061570, 304036170, 608072289, 1387247580, 2774495160

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

References

• S. J. Cyvin et al., Enumeration and classification of certain polygonal systems...: annelated catafusenes, J. Chem. Inform. Comput. Sci., 34 (1994), 1174-1180.

Crossrefs

Cf. A002212 (U), A055879 (V).

Formula

G.f.: U(z^2)*V(z) + V(z)/z - V(z^3) - 1, where U(z) = (1 - 3*z - sqrt(1-6*z+ 5*z^2)) / (2*z) and V(z) = (1 - z^2 - sqrt(1-6*z^2+5*z^4)) / (2*z*(1-z)) (from eq. (29) of the Cyvin et al. paper). - Emeric Deutsch, May 02 2004

Extensions

More terms from Emeric Deutsch, May 02 2004