is never prime, because it factorises as .
, so that is not prime either. It is not known whether there is any value of n greater than 4 for which the Fermat number is prime.
is never prime, because it factorises as .
, so that is not prime either. It is not known whether there is any value of n greater than 4 for which the Fermat number is prime.
Already done: Perfect Numbers
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