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19816Re: Find non-integer A such that floor(A^n) is never prime?

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  • David Broadhurst
    Jan 16, 2009
      --- In primenumbers@yahoogroups.com, "jbrennen" <jfb@> wrote:

      > is floor(sqrt(18)^n) ever prime? :)

      How about n = 10675 for a BPSW probable prime?

      It seems that Poisson can be cheated by posting
      a remark like this:

      > Since there is no PRP for n < 10^4, we might need to go up
      > to something like n = 10^4*18^2 to get a half-way decent
      > chance of a prime

      and then Poisson's gremlins almost immediately oblige
      with a hit, before I can turn off the process:

      ? print(ispseudoprime(sqrtint(18^10675)));
      1

      David Broadhurst
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