Number of finite subgroups of GO3.
John Conway
conway at math.Princeton.EDU
Wed Dec 15 22:05:56 CET 1999
The number of groups of order n , counted up to conjugacy, is given by:
n = 1 2 3 4 5 6 7 8 9 ...
1 3 1 5 1 5 1 7 1 5 1 8 1 5 1 7 1 5 1 7 1 5 1 10 1 5 1 7 1 5 1 7 1 5 1
namely it has the period 1 5 1 7 except that
g(2) = 3, g(4) = 5, g(12) = 8, g(24) = 10, g(48) = g(60) = g(120) = 8.
Neil - did I give you this one already?
In SO3 ge get a similar sequence - let me work it out - the groups are
nn, of order n
22n, of order 2n
332,432,532 of orders 12,24,60
but we have the coincidence 22 = 221 indicated below:
11 22 33 44 55 66
=221 222 223
so the sequence is
1 1 1 2 1 2 1 2 1 2 1 3 1 2 1 2 1 2 1 2 1 2 1 3 1 2 1 ...
the only other exception to the 1 2 period being f(60) = 3.
Regards, JHC
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