<P> Other examples of prime - generating formulas come from Mills' theorem and a theorem of Wright . These assert that there are real constants A> 1 (\ displaystyle A> 1) and μ (\ displaystyle \ mu) such that </P> <Dl> <Dd> ⌊ A 3 n ⌋ and ⌊ 2 ⋯ 2 2 μ ⌋ (\ displaystyle \ left \ lfloor A ^ (3 ^ (n)) \ right \ rfloor (\ text (and)) \ left \ lfloor 2 ^ (\ cdots ^ (2 ^ (2 ^ (\ mu)))) \ right \ rfloor) </Dd> </Dl> <Dd> ⌊ A 3 n ⌋ and ⌊ 2 ⋯ 2 2 μ ⌋ (\ displaystyle \ left \ lfloor A ^ (3 ^ (n)) \ right \ rfloor (\ text (and)) \ left \ lfloor 2 ^ (\ cdots ^ (2 ^ (2 ^ (\ mu)))) \ right \ rfloor) </Dd> <P> are prime for any natural number n (\ displaystyle n) in the first formula, and any number of exponents in the second formula . Here ⌊ ⋅ ⌋ (\ displaystyle \ lfloor () \ cdot () \ rfloor) represents the floor function, the largest integer less than or equal to the number in question . However, these are not useful for generating primes, as the primes must be generated first in order to compute the values of A (\ displaystyle A) or μ (\ displaystyle \ mu). </P>

Is there a number which has no factor