A006724 Number of fixed n-celled self-avoiding polygons on square lattice. (Formerly M1637)

1, 2, 6, 19, 63, 216, 756, 2684, 9638, 34930, 127560, 468837, 1732702, 6434322, 23993874, 89805691, 337237337, 1270123530, 4796310672, 18155586993, 68874803609, 261803388854, 996971935098, 3802944302442, 14528816598358

Offset

1,2

Comments

Translations, rotations and reflections are not allowed.

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

I. Jensen, Table of n, a(n) for n = 1..42 (from link below)

I. G. Enting and A. J. Guttmann, On the area of square lattice polygons, J. Statist. Phys., 58 (1990), 475-484. See p. 477.

I. Jensen, More terms

Tomás Oliveira e Silva, Enumeration of polyominoes

Crossrefs

Cf. A002931.

Sequence in context: A059712 A059713 A109262 * A057409 A346157 A141771

Adjacent sequences: A006721 A006722 A006723 * A006725 A006726 A006727

Keyword

nonn,nice

Author

N. J. A. Sloane, Simon Plouffe

Status

approved