[seqfan] Re: Nonmembers of Range of Euler Phi Function

Ray Chandler rayjchandler at sbcglobal.net
Sun Sep 19 23:53:15 CEST 2010


> Calculating up to n=17, I find that these numbers all have 
> the form 2^n * p, where p is 3, 7, 17, 19, 31, 47.  It's not 
> clear what sequence p is.
> Might be A064699
> 
> Tony
> 
Using phiinv function defined in Mma code for A006511, I confirm terms
continue as Tony describes above at least through a(582)=2^582*47, where the
process seems to hang.
Ray





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