A157223 Number of primitive inequivalent oblique sublattices of centered rectangular lattice of index n.

0, 1, 1, 2, 2, 5, 3, 4, 5, 8, 5, 10, 6, 11, 10, 10, 8, 17, 9, 16, 14, 17, 11, 20, 14, 20, 17, 22, 14, 34, 15, 22, 22, 26, 22, 34, 18, 29, 26, 32, 20, 46, 21, 34, 34, 35, 23, 44, 27, 44, 34, 40, 26, 53, 34, 44, 38, 44, 29, 68, 30, 47, 46, 46, 40, 70, 33, 52, 46

Offset: 1

Author

N. J. A. Sloane, Feb 25 2009

Keywords

• nonn

Links

• John S. Rutherford, Sublattice enumeration. IV. Equivalence classes of plane sublattices by parent Patterson symmetry and colour lattice group type, Acta Cryst. (2009). A65, 156-163. [See Table 4.]

Crossrefs

Cf. A060594 (primitive mirror-symmetric sublattices), A145390 (all mirror-symmetric sublattices), A145391 (all sublattices), A001615, A304182.

Formula

a(n) = (A001615(n) - A060594(n))/2. - Andrey Zabolotskiy, May 09 2018

Extensions

New name and more terms from Andrey Zabolotskiy, May 09 2018