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Search: id:A091071
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| A091071 |
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Number of normalizers of subgroups of the symmetric group on n points. |
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+0
1
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| 1, 1, 1, 2, 4, 5, 12, 19, 42, 72, 127, 196, 500
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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G. Pfeiffer, Counting Transitive Relations, preprint, 2004.
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LINKS
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G. Pfeiffer, Subgroups.
G. Pfeiffer, Counting Transitive Relations, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.2.
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EXAMPLE
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a(3)=2 because of the 4 (conjugacy classes of) subgroups of Sym(3) only 2 (Sym(2) and Sym(3)) are normalizers of subgroups.
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CROSSREFS
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Cf. A000638 (subgroups of Sym(n)), A091070 (stabilizers of partial orders).
Sequence in context: A090847 A056984 A117556 this_sequence A050599 A102932 A128457
Adjacent sequences: A091068 A091069 A091070 this_sequence A091072 A091073 A091074
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KEYWORD
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hard,nonn
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AUTHOR
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Goetz Pfeiffer (goetz.pfeiffer(AT)nuigalway.ie), Jan 21 2004
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