A059713 Number of multi-directed animals on the square lattice.

1, 2, 6, 19, 63, 214, 738, 2571, 9020, 31806, 112572, 399548, 1421145, 5063254, 18062902, 64505148, 230547424, 824547052, 2950565215, 10562978104

Offset

1,2

Comments

This class of animals is in bijection with a simple class of heaps of dimers. It generalizes directed animals.

References

M. Bousquet-Mélou and A. Rechnitzer, Lattice animals and heaps of dimers, Discrete Math. 258 (2002), no. 1-3, 235-274.

Links

Table of n, a(n) for n=1..20.

M. Bousquet-Mélou and A. Rechnitzer, Lattice animals and heaps of dimers

Formula

The generating function is known in closed form. Closed, but big. It is proved to be non-D-finite.

Crossrefs

Directed animals: A005773.

Sequence in context: A120900 A284216 A059712 * A109262 A006724 A057409

Adjacent sequences: A059710 A059711 A059712 * A059714 A059715 A059716

Keyword

nonn

Author

Mireille Bousquet-Mélou, Feb 08 2001

Status

approved