login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A091071 Number of normalizers of subgroups of the symmetric group on n points. 0
1, 1, 1, 2, 4, 5, 12, 19, 42, 72, 127, 196, 500 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

REFERENCES

G. Pfeiffer, Counting Transitive Relations, preprint, 2004.

LINKS

Table of n, a(n) for n=0..12.

G. Pfeiffer, Subgroups.

G. Pfeiffer, Counting Transitive Relations, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.2.

EXAMPLE

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.

CROSSREFS

Cf. A000638 (subgroups of Sym(n)), A091070 (stabilizers of partial orders).

Sequence in context: A090847 A056984 A117556 * A050599 A102932 A128457

Adjacent sequences:  A091068 A091069 A091070 * A091072 A091073 A091074

KEYWORD

hard,nonn

AUTHOR

Goetz Pfeiffer (goetz.pfeiffer(AT)nuigalway.ie), Jan 21 2004

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 3 08:48 EST 2016. Contains 278698 sequences.