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A091070
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Number of automorphism groups of partial orders on n points.
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1
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1, 1, 2, 3, 6, 8, 16, 21, 41, 57, 103, 140, 276
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| G. Pfeiffer, Subgroups.
G. Pfeiffer, Counting Transitive Relations, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.2.
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EXAMPLE
| a(3)=3 because of the 5 partial orders on 3 points, 2 have trivial automorphism group, 2 have an automorphism of order 2 and one has the full symmetric group as its automorphism group; thus 3 different (conjugacy classes of) subgroups occur.
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CROSSREFS
| Cf. A000638 (subgroups of the symmetric group), A000112 (partial orders).
Sequence in context: A048809 A047001 A174021 * A133586 A141348 A029867
Adjacent sequences: A091067 A091068 A091069 * A091071 A091072 A091073
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KEYWORD
| hard,nonn
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AUTHOR
| Goetz Pfeiffer (goetz.pfeiffer(AT)nuigalway.ie), Jan 21 2004
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