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%I #19 Jul 07 2024 13:20:47
%S 2,8,10,64,76,118,120,258,303,332,364,528,811,1270,1362,1607,2091,
%T 2572,3596,8190,34271,37860,37938
%N Numbers k such that 2*13^k - 1 is prime.
%C a(21) > 14400. - _Jinyuan Wang_, Feb 26 2020
%t Select[Range[5000], PrimeQ[(2 13^# - 1)] &] (* _Vincenzo Librandi_, Oct 05 2012 *)
%o (Magma) /* The code gives only the terms up to 1607: */ [n: n in [0..1700] | IsPrime(2*13^n-1)];
%o (PARI) is(n)=ispseudoprime(2*13^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017
%K nonn,more
%O 1,1
%A _Vincenzo Librandi_, Mar 10 2010
%E a(14)-a(19) from _Vincenzo Librandi_, Oct 05 2012
%E a(20) from _Jinyuan Wang_, Feb 26 2020
%E a(21)-a(23) from _Michael S. Branicky_, Jul 07 2024
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