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A145393 Number of sublattices of index n fixed by a certain point group (see reference for precise definition). 0
1, 2, 2, 4, 3, 5, 3, 7, 5, 7, 4, 11, 5, 8, 8, 12, 6, 13, 6, 15, 10, 11, 7, 21, 10, 13, 12, 18, 9, 22, 9, 21, 14, 16, 14, 29, 11, 17, 16, 29, 12, 28, 12, 25, 23, 20, 13, 39, 16, 27, 20, 29, 15, 34, 20, 36, 22, 25, 16, 50, 17, 26, 29, 38, 24, 40, 18, 36, 26, 40 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

REFERENCES

John S. Rutherford, Sublattice enumeration. IV. Equivalence classes of plane sublattices by parent Patterson symmetry and colour lattice group type, Acta Cryst. (2009). A65, 156163. [See Table 2].

FORMULA

a(n) = (A000203 + A002654 + A069735 + A145390)/4. [Rutherford] - N. J. A. Sloane, Mar 13 2009

CROSSREFS

Sequence in context: A133438 A086671 A054346 * A132802 A204900 A070803

Adjacent sequences:  A145390 A145391 A145392 * A145394 A145395 A145396

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Feb 23 2009

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Last modified February 15 23:32 EST 2012. Contains 205860 sequences.