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A057200
Numbers k such that 2^k + 17 is prime.
21
1, 13, 21, 33, 81, 129, 285, 297, 769, 3381, 4441, 7065, 77121, 133437, 184189, 191745, 1279921
OFFSET
1,2
COMMENTS
a(17) > 5*10^5. - Robert Price, Oct 05 2015
For numbers k in this sequence, 2^(k-1)*(2^k+17) has deficiency 18 (see A223608). - M. F. Hasler, Jul 18 2016
All terms are odd. - Elmo R. Oliveira, Nov 19 2023
LINKS
Henri Lifchitz and Renaud Lifchitz (Editors), Search for 2^n+17, PRP Top Records.
MATHEMATICA
Do[ If[ PrimeQ[ 2^n + 17 ], Print[ n ]], {n, 0, 11811} ]
Select[Range[10000], PrimeQ[2^# + 17] &] (* Vincenzo Librandi, Aug 28 2015 *)
PROG
(Magma) [n: n in [0..1000] | IsPrime(2^n+17)]; // Vincenzo Librandi, Aug 28 2015
(PARI) is(n)=isprime(2^n+17) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
Cf. A223608.
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), A057197 (2^k+15), this sequence (2^k+17), A057221 (2^k+19), A057201 (2^k+21), A057203 (2^k+23).
Sequence in context: A164498 A164485 A164447 * A164454 A164426 A164473
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Sep 16 2000
EXTENSIONS
a(13)-a(16) from Robert Price, Aug 24 2015
Edited by M. F. Hasler, Jul 18 2016
a(17) found by Stefano Morozzi, added by Elmo R. Oliveira, Nov 19 2023
STATUS
approved