OFFSET
1,2
COMMENTS
Infinite under Dickson's conjecture. [Charles R Greathouse IV, Jul 06 2011]
No n can be a multiple of 3. If it is 1 mod 3, it cannot end in 3 or 8. If it is 2 mod 3, it cannot end in 1 or 6. One can see the potential of iterative chains producing primes.
EXAMPLE
For n=37, 4*37+3=151 and 16*37+15=607.
MATHEMATICA
Select[Range[500], PrimeQ[4# + 3] && PrimeQ[16# + 15] &] (* Alonso del Arte, Jul 06 2011 *)
PROG
(PARI) for(n=1, 1e3, if(isprime(4*n+3)&&isprime(16*n+15), print1(n", "))) \\ Charles R Greathouse IV, Jul 06 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot, Jul 06 2011
STATUS
approved