OFFSET
1,2
EXAMPLE
a(1)=1 because 1*12-5=7, 1*12+1=13, and 1*12+7=19 are all prime.
PROG
(Magma) [n: n in [1..1000]|IsPrime(12*n-5) and IsPrime(12*n+1) and IsPrime(12*n+7)] // Vincenzo Librandi, Dec 06 2010
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Juri-Stepan Gerasimov, Mar 17 2010
EXTENSIONS
Corrected by Charles R Greathouse IV, Mar 18 2010
a(18)-a(51) from Vincenzo Librandi, Mar 20 2010
STATUS
approved