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

Author

Mireille Bousquet-Mélou, Feb 08 2001

Keywords

• nonn

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

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

Crossrefs

Directed animals: A005773.

Formula

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