The interesting question would be to find a function for which almost all f(Z+) is prime; are there any simple functions for which the asymptotic density of primes in f(Z+) is a larger order of magnitude than 1/log(n)? On Sun, Apr 28, 2019 at 10:32 PM Mike Stay <metaweta@gmail.com> wrote:
On Sun, Apr 28, 2019 at 9:28 PM Dan Asimov <dasimov@earthlink.net> wrote:
II. What kinds of nice functions f : Z+ —> Z+ are known to have infinitely many primes in their image:
|f(Z+) ∩ Primes| = oo
???
f(z) = z and f(z) = 2z+1 come to mind... -- Mike Stay - metaweta@gmail.com http://math.ucr.edu/~mike https://reperiendi.wordpress.com
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