Thread: "Rare" Primes View Single Post
2008-08-29, 14:47   #57
retina
Undefined

"The unspeakable one"
Jun 2006
My evil lair

137438 Posts

Quote:
 Originally Posted by R.D. Silverman Although not explicitly stated, I believe that the domain is N. Now, f(x) is prime for x = 0, 4 and no other. If you accept the more general definition of prime (i.e. not restricted to just N) then f(x) will be prime i.o. (although a proof is lacking). If we allow x \in R, then f(x) is indeed prime the required number of times.
Thanks, yeah I was assuming x is an element of R.

f(x)=398-x^2; x element of N

To satisfy Mini-Geek's requirement of total primes: f(x)=143-x^2; x element of Z

Last fiddled with by retina on 2008-08-29 at 15:11 Reason: Forgot to specifiy the Z set