OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
991 is in the sequence because 991+(990/3) = 1321 and 991-(990/3) = 661, which are primes;
2143 is in the sequence because 2143+(2142/3) = 2857 and 2143-(2142/3) = 1429, which are primes.
MATHEMATICA
Select[Prime[Range[50000]], PrimeQ[# + (# - 1) / 3]&&PrimeQ[# - (# - 1) / 3]&] (* Vincenzo Librandi, Jun 15 2013 *)
PROG
(Magma) [p: p in PrimesInInterval(5, 40000)| IsPrime((4*p-1) div 3 ) and IsPrime((2*p+1) div 3)]; // Vincenzo Librandi, Jun 15 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Joseph Stephan Orlovsky, Apr 27 2008
EXTENSIONS
More terms from Vincenzo Librandi, Jun 15 2013
STATUS
approved