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A066586
Number of normal subgroups of the group of n X n signed permutations matrices (described in sequence A066051).
0
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, ...
FORMULA
For n>=5 a(n) = 9.
CROSSREFS
Cf. A066051.
Sequence in context: A370810 A071814 A121248 * A146974 A133160 A128906
KEYWORD
nonn
AUTHOR
Sharon Sela (sharonsela(AT)hotmail.com), Jan 07 2002
STATUS
approved