A193179 Number of classes of two-dimensional generalized Bravais lattices with 2n-fold symmetry.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 3, 1, 2, 9, 1, 9, 17, 1, 32, 1, 3, 34, 19, 2, 5, 121, 1, 211, 55, 1, 201, 695, 32, 43

Offset

2,22

Comments

Related to class numbers of cyclotomic fields, although the precise relationship is not clear to me. Compare A000927.

References

Mermin, N. David; Rokhsar, Daniel S.; and Wright, David C.; Beware of 46-fold symmetry: the classification of two-dimensional quasicrystallographic lattices. Phys. Rev. Lett. 58 (1987), 2099-2101.

Links

Table of n, a(n) for n=2..49.

Crossrefs

See A193175 for values of 2n such that a(n) = 1.

Cf. A000927.

Sequence in context: A109848 A104146 A326405 * A133705 A046111 A131779

Adjacent sequences: A193176 A193177 A193178 * A193180 A193181 A193182

Keyword

nonn

Author

N. J. A. Sloane, Jul 17 2011

Status

approved