

A193179


Number of classes of twodimensional generalized Bravais lattices with 2nfold symmetry.


1



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
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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 46fold symmetry: the classification of twodimensional quasicrystallographic lattices. Phys. Rev. Lett. 58 (1987), 20992101.


LINKS



CROSSREFS

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


KEYWORD

nonn


AUTHOR



STATUS

approved



