A006818 Trails of length n on hexagonal lattice. (Formerly M4203)

1, 6, 30, 150, 738, 3570, 17118, 81498, 385710, 1817046, 8528478, 39903462, 186198642, 866861394, 4027766490, 18681900270, 86518735722, 400136695074, 1848320799438, 8528448008214

Offset

0,2

Comments

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

References

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

Links

Table of n, a(n) for n=0..19.

A. J. Guttmann, Lattice trails II: numerical results, J. Phys. A 22 (1989), 575-588.

G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2

Crossrefs

Sequence in context: A075886 A001412 A162937 * A006819 A163317 A342807

Adjacent sequences: A006815 A006816 A006817 * A006819 A006820 A006821

Keyword

nonn,walk,more

Author

N. J. A. Sloane

Extensions

a(17)-a(19) from Sean A. Irvine, Aug 15 2020

Status

approved