[seqfan] At least the first 6 values are the same for A002884 and for A061350(2^n)

Jonathan Post jvospost3 at gmail.com
Wed Aug 11 17:50:23 CEST 2010

Is it true (I just woke up and don't clearly recall my Group Theory)
that  A002884  is A061350(2^n)?

A002884  	Number of nonsingular n X n matrices over GF(2) (order of
Chevalley group A_n (2)).
(Formerly M4302 N1798) 		
	1, 1, 6, 168, 20160, 9999360, ...

A061350  	Maximal size of Aut(G) where G is a finite Abelian group of order n.

If so, a nice comment would be  Hall's:

"The sum of the reciprocals of the orders of all the Abelian groups of
order a power of p is equal to the sum of the reciprocals of the
orders of their groups of automorphisms."

Link to:

John Baez:
This Week’s Finds in Mathematical Physics (Week 300)


This is the last of the old series of This Week’s Finds. Soon the new
series will start, focused on technology and environmental issues —
but still with a hefty helping of math, physics, and other science....

But now… the grand finale of This Week’s Finds in Mathematical Physics!

I’d like to take everything I’ve been discussing so far and wrap it up
in a nice neat package. Unfortunately that’s impossible – there are
too many loose ends. But I’ll do my best: I’ll tell you how to
categorify the Riemann zeta function. This will give us a chance to
visit lots of our old friends one last time: the number 24, string
theory, zeta functions, torsors, Joyal’s theory of species,
groupoidification, and more.

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