OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
31, 6*31-7=179, 6*31+7=193 are all primes.
MATHEMATICA
Select[Range[5000], PrimeQ[ # ] && PrimeQ[6# + 7] && PrimeQ[6# - 7] &]
Select[Prime[Range[3000]], PrimeQ[6 # - 7] && PrimeQ[6 # + 7]&] (* Vincenzo Librandi, Apr 09 2013 *)
PROG
(Magma) [p: p in PrimesUpTo(2600) | IsPrime(6*p-7) and IsPrime(6*p+7)]; // Vincenzo Librandi, Apr 09 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zerinvary Lajos, Mar 30 2007
STATUS
approved