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Old 2011-04-13, 19:58   #3
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Jul 2009

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Originally Posted by CRGreathouse View Post
The problem is hard and in general cannot be done symbolically.

For that one you'll need a special function like Lambert's W, or numerical techniques. I think it's exp(W(log N)). W(x) is about log x - log log x, so this is roughly exp(log log N - log log log N) = log N / log log N, where log is the natural log.
if he didn't want work I'd say use PARI's ispower() with a loop through base values.

Last fiddled with by science_man_88 on 2011-04-13 at 19:58
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