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%I #23 Dec 11 2023 11:44:38
%S 1,2,3,4,5,6,8,10,11,12,15,16,22,23,26,30,32,40,42,46,61,72,76,155,
%T 180,198,203,310,328,342,508,510,515,546,808,1563,2772,3882,3940,4840,
%U 7518,11118,11552,11733,12738,12858,17421,44122,64660,163560,172455,180496,325866,481840,1009168
%N Numbers k such that 2^k + 15 is prime.
%C a(55) > 5*10^5. - _Robert Price_, Sep 14 2015
%C For these numbers k, 2^(k-1)*(2^k+15) has deficiency 16 (see A125248). - _M. F. Hasler_, Jul 18 2016
%H Henri Lifchitz and Renaud Lifchitz (Editors), <a href="http://www.primenumbers.net/prptop/searchform.php?form=2%5En%2B15">Search for 2^n+15</a>, PRP Top Records.
%e For k = 5, 2^5 + 15 = 47 is prime.
%e For k = 15, 2^15 + 15 = 32783 is prime.
%t Do[ If[ PrimeQ[ 2^n + 15 ], Print[n]], { n, 1, 12422 }]
%t Select[Range[15000], PrimeQ[2^# + 15] &] (* _Vincenzo Librandi_, Aug 28 2015 *)
%o (Magma) [n: n in [0..1500] | IsPrime(2^n+15)]; // _Vincenzo Librandi_, Aug 28 2015
%o (PARI) for(n=1,9e9,ispseudoprime(2^n+15)&&print1(n",")) \\ _M. F. Hasler_, Jul 18 2016
%Y Cf. A094076, A125248.
%Y Cf. A019434 (primes 2^k+1), A057732 (2^k+3), A059242 (2^k+5), A057195 (2^k+7), A057196 (2^k+9), A102633 (2^k+11), A102634 (2^k+13), this sequence (2^k+15), A057200 (2^k+17), A057221 (2^k+19), A057201 (2^k+21), A057203 (2^k+23).
%K nonn
%O 1,2
%A _Robert G. Wilson v_, Sep 15 2000
%E a(45)-a(53) from _Robert Price_, Dec 06 2013
%E a(54) from _Robert Price_, Sep 14 2015
%E a(55) from Stefano Morozzi, added by _Elmo R. Oliveira_, Dec 11 2023
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