OFFSET
1,2
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[100], SquareFreeQ[#] && PrimeQ[6# - 1] && PrimeQ[6# + 1] &] (* Indranil Ghosh, Mar 17 2017 *)
PROG
{MAGMA) [n: n in [1..700] | IsSquarefree(n) and IsPrime(6*n-1) and IsPrime(6*n+1)];
(PARI) is(n)=isprime(6*n-1) && isprime(6*n+1) && issquarefree(n) \\ Charles R Greathouse IV, Mar 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Juri-Stepan Gerasimov, Mar 17 2017
STATUS
approved