OFFSET
1,2
COMMENTS
Subsequence of A056956.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = (A022005(n)-1)/6.
MATHEMATICA
Select[Range[1437], Union[PrimeQ[6 # + {1, 5, 7}]] == {True} &] (* T. D. Noe, Aug 27 2012 *)
PROG
(PARI) for(n=1, 2000, if(isprime(6*n+1)&&isprime(6*n+5)&&isprime(6*n+7), print(n", ")))
(Magma) [n: n in [1..1000] | forall{6*n+r: r in [1, 5, 7] | IsPrime(6*n+r)}]; // Bruno Berselli, Aug 27 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Aug 27 2012
STATUS
approved