A066586 Number of normal subgroups of the group of n X n signed permutations matrices (described in sequence A066051).

2, 6, 9, 11, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9

Offset

1,1

Comments

The similar sequence for the "ordinary" symmetric group S_n is 1, 2, 3, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, ...

Links

Table of n, a(n) for n=1..87.

Formula

For n>=5 a(n) = 9.

Crossrefs

Cf. A066051.

Sequence in context: A370802 A370810 A071814 * A146974 A133160 A128906

Adjacent sequences: A066583 A066584 A066585 * A066587 A066588 A066589

Keyword

nonn

Author

Sharon Sela (sharonsela(AT)hotmail.com), Jan 07 2002

Status

approved