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A145391 Number of sublattices of index n fixed by a certain point group (see reference for precise definition). 0
1, 2, 3, 5, 4, 7, 5, 10, 8, 10, 7, 17, 8, 13, 14, 19, 10, 21, 11, 24, 18, 19, 13, 35, 17, 22, 22, 31, 16, 38, 17, 36, 26, 28, 26, 50, 20, 31, 30, 50, 22, 50, 23, 45, 42, 37, 25, 69, 30, 48, 38, 52, 28, 62, 38, 65, 42, 46, 31, 90, 32, 49, 55, 69, 44, 74, 35, 66, 50, 74 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..70.

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 2.]

FORMULA

a(n) = (A000203 + A145390)/2. [Rutherford] - N. J. A. Sloane, Mar 13 2009

CROSSREFS

Sequence in context: A085180 A114750 A234923 * A057756 A160051 A082746

Adjacent sequences:  A145388 A145389 A145390 * A145392 A145393 A145394

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 23 2009

STATUS

approved

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Last modified October 24 05:44 EDT 2014. Contains 248500 sequences.