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Numbers k such that 3*2^k + 7 is prime.
2

%I #29 Sep 02 2024 16:28:55

%S 1,2,3,5,6,9,10,11,19,22,30,35,41,91,101,125,261,706,750,1315,1629,

%T 2082,2979,3029,3077,3950,4097,5491,5746,10761,12946,14770,15642,

%U 30006,34157,34722,48499,62862

%N Numbers k such that 3*2^k + 7 is prime.

%C According to PRP Records, this sequence contains 131867, 164205, 185429, 232750, 256149, 295139, 315067, 368489. - _Jason Yuen_, Sep 02 2024

%H Henri Lifchitz and Renaud Lifchitz, <a href="http://primenumbers.net/prptop/searchform.php?form=3*2%5Ek%2B7&amp;action=Search">PRP Records</a>.

%t Do[ If[ PrimeQ[ 3*2^n + 7 ], Print[n] ], {n, 1, 3000} ]

%o (PARI) is(n)=ispseudoprime(3*2^n+7) \\ _Charles R Greathouse IV_, Jun 13 2017

%Y Cf. A059747.

%K nonn,more

%O 1,2

%A _Robert G. Wilson v_, Feb 10 2001

%E More terms from _Robert G. Wilson v_, Jan 28 2003

%E a(33) from _Michael S. Branicky_, Jan 09 2023

%E a(34) from _Michael S. Branicky_, Jan 12 2023

%E a(35)-a(37) from _Michael S. Branicky_, Apr 06 2023

%E a(38) from _Michael S. Branicky_, Jul 31 2024