OFFSET
1,1
FORMULA
p, 2p-9 and 2p+9 all are positive and are primes (hence we omit p=2).
MATHEMATICA
Select[Range[7, 6000], PrimeQ[ # ] && PrimeQ[2# + 9] && PrimeQ[2# - 9] &]
okQ[n_]:=Module[{c=2n}, PrimeQ[c+9]&&PrimeQ[c-9]]; Select[Prime[ Range[5, 500]], okQ] (* Harvey P. Dale, Apr 25 2011 *)
PROG
(Magma) [p: p in PrimesUpTo(3200)| IsPrime(2*p+9) and IsPrime(2*p-9) ]; // Vincenzo Librandi, Jan 28 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Feb 16 2005
STATUS
approved