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A059621 Numbers k such that (5*3^k + 7)/2 is prime. 1

%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^k-7)/2 is prime).

%K nonn,more

%O 1,2

%A _Robert G. Wilson v_, Feb 19 2001

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Last modified August 4 10:06 EDT 2021. Contains 346447 sequences. (Running on oeis4.)