1,3

Table of n, a(n) for n=1..68.

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.]

a(n) = (A001615(n) - A000089(n))/2. - Andrey Zabolotskiy, May 09 2018

Cf. A000089 (primitive square sublattices), A002654 (all square sublattices), A145392 (all sublattices), A001615, A304182.

Sequence in context: A329282 A197289 A161888 * A097914 A286633 A286586

Adjacent sequences: A157221 A157222 A157223 * A157225 A157226 A157227

nonn

N. J. A. Sloane, Feb 25 2009

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

approved