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A145392
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Number of sublattices of index n fixed by a certain point group (see reference for precise definition).
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0
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1, 2, 2, 4, 4, 6, 4, 8, 7, 10, 6, 14, 8, 12, 12, 16, 10, 20, 10, 22, 16, 18, 12, 30, 17, 22, 20, 28, 16, 36, 16, 32, 24, 28, 24, 46, 20, 30, 28, 46, 22, 48, 22, 42, 40, 36, 24, 62, 29, 48, 36, 50, 28, 60, 36, 60, 40, 46, 30, 84, 32, 48, 52, 64, 44, 72, 34, 64, 48, 72
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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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].
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FORMULA
| a(n) = (A000203 + A002654)/2. [Rutherford] - N. J. A. Sloane, Mar 13 2009
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CROSSREFS
| Sequence in context: A171462 A075857 A023817 * A034974 A048275 A109874
Adjacent sequences: A145389 A145390 A145391 * A145393 A145394 A145395
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Feb 23 2009
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