A007275 Walks on hexagonal lattice using each point at most three times.

1, 6, 36, 216, 1296, 7776, 46440, 276054, 1633848, 9633366, 56616132, 331847118, 1940715960, 11327957196, 66010769382, 384094025382, 2231978658906

Offset: 0

Author

Simon Plouffe

Keywords

• nonn
• walk

Comments

The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.

Guttmann et al. has incorrect a(10) = 56616140, a(11) = 331847200, and a(12) = 1940717000. - Sean A. Irvine, Dec 03 2017

References

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

Links

• A. J. Guttmann, C. Byrnes and N. E. Frankel, A generalized self-avoiding walk, J. Phys. A 17 (1984), L457-L461.
• G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2

Crossrefs

Cf. A001334, A007274.

Extensions

Title improved, a(10)-a(12) corrected, and a(15)-a(16) added by Sean A. Irvine, Dec 03 2017