OFFSET
1,3
COMMENTS
The polygons and the hole are self-avoiding and mutually-avoiding, i.e., no degree four vertices are allowed. Translations are allowed, rotations and reflections are not allowed. The contribution of the holes to the perimeter is counted. The number of the holes is not limited, possibly no holes.
LINKS
I. Jensen, Table of n, a(n) for n = 1..43 (from link below)
Anthony J. Guttmann, Iwan Jensen, Ling Heng Wong and Ian G. Enting, Punctured polygons and polyominoes on the square lattice, J. Phys. A, Vol. 33 (2000) 1735-1764.
Iwan Jensen, List of terms
Iwan Jensen, Series expansions for self-avoiding polygons
CROSSREFS
KEYWORD
nonn
AUTHOR
Markus Voege (markus.voege(AT)inria.fr), Nov 23 2003
STATUS
approved
