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A080803 Number of vertices of minimal graph with an automorphism group of order n. +0
2
0, 2, 9, 4, 15, 3, 14, 4, 15, 5, 22, 5, 26, 7, 21, 6, 34, 9, 38, 7, 21, 11, 46, 4, 30, 13, 24, 9, 58, 14, 62 (list; graph; listen)
OFFSET

1,2

COMMENT

Most terms were found in the thread "Automorphismengruppen von Graphen" in the German newsgroup "de.sci.mathematik" (mostly by Hauke Klein). The terms a(9)=15, a(15)=21, a(21)=23, a(27)=24, a(30)=14 still need verification.

The value A080803(21) = 21 is due to Gordon Royle, who found a graph with 21 vertices whose automorphism group is non-Abelian of order 21 (a 2'-Hall subgroup of the group PSL_2(7)).

LINKS

Eric Weisstein's World of Mathematics, Automorphism Group

EXAMPLE

a(4)=4 because the graph with 4 vertices and exactly one edge has an automorphism group of order 4 and no smaller graph has exactly 4 automorphisms.

CROSSREFS

Cf. A058890.

Adjacent sequences: A080800 A080801 A080802 this_sequence A080804 A080805 A080806

Sequence in context: A070700 A115290 A021343 this_sequence A022157 A065599 A054789

KEYWORD

more,nice,nonn

AUTHOR

Jens Voss (jens(AT)voss-ahrensburg.de), Mar 26 2003

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Last modified January 8 02:43 EST 2009. Contains 152824 sequences.


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