%I
%S 1,3,7,9,19,27,57,69,163,175,357,379,3045
%N Numbers k such that (5*3^k + 7)/2 is prime.
%C a(14) > 30163.  _Jinyuan Wang_, Jan 28 2020
%t Do[ If[ PrimeQ[ (5*3^n + 7)/2 ], Print[n] ], {n, 0, 10000} ]
%o (PARI) is(n)=ispseudoprime((5*3^n+7)/2) \\ _Charles R Greathouse IV_, Jun 13 2017
%o (MAGMA) [k: k in [0..1000]  IsPrime((5*3^k + 7) div 2)]; // _Jinyuan Wang_, Jan 28 2020
%Y Cf. A059622 ((5*3^k7)/2 is prime).
%K nonn,more
%O 1,2
%A _Robert G. Wilson v_, Feb 19 2001
