A006724 Number of fixed n-celled self-avoiding polygons on square lattice.

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

Author

N. J. A. Sloane, Simon Plouffe

Keywords

• nonn
• nice

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
• Hugo Tremblay and Julien Vernay, On the generation of discrete figures with connectivity constraints, RAIRO-Theor. Inf. Appl. (2024) Vol. 58, Art. No. 16. See p. 13.

Crossrefs

Cf. A002931.