%I #18 Jul 09 2024 08:53:40
%S 2,4,6,10,12,13,19,43,48,64,72,97,187,190,336,348,676,2484,2719,3298,
%T 4726,9901,24466,43980,56302,72175
%N Numbers k such that 2*3^k - 5 is prime.
%C a(24) > 37734. - _Jinyuan Wang_, Jan 20 2020
%t Do[ If[ PrimeQ[ 2*3^n - 5 ], Print[ n ] ], {n, 1, 2500} ]
%t Select[Range[10000],PrimeQ[2*3^#-5]&] (* _Harvey P. Dale_, Jan 19 2018 *)
%o (PARI) is(n)=ispseudoprime(2*3^n-5) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. A057911 (2*3^k + 5 is prime).
%K nonn,more
%O 1,1
%A _Robert G. Wilson v_, Nov 16 2000
%E a(23) from _Jinyuan Wang_, Jan 20 2020
%E a(24)-a(26) from _Michael S. Branicky_, Jul 09 2024