login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A088702
Number of polygons with polygonal holes on the square lattice enumerated by half-perimeter.
1
0, 1, 2, 7, 28, 124, 588, 2939, 15292, 82168, 453376, 2558074, 14712038, 86029132, 510455002, 3068304865, 18658787150, 114663168405, 711391109162, 4452321247688, 28090360338572, 178550339417087, 1142799275636690
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.
REFERENCES
A. J. Guttmann, I. Jensen, L. H. Wong and I. G. Enting, J. Phys. A, Vol. 33 (2000) 1735-1764.
LINKS
CROSSREFS
Cf. A002931 (self-avoiding polygons), A056634 (self-avoiding polygons with exactly one hole), A056638 (self-avoiding polygons with exactly two holes), A056639 (self-avoiding polygons with exactly three holes).
Sequence in context: A253787 A060379 A002931 * A112565 A227845 A118926
KEYWORD
nonn
AUTHOR
Markus Voege (markus.voege(AT)inria.fr), Nov 23 2003
STATUS
approved