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Numbers k such that 297*2^k-1 is prime.
1

%I #26 Jan 17 2019 10:08:17

%S 1,2,4,8,9,10,14,18,24,25,30,42,48,49,56,90,97,182,336,348,434,546,

%T 769,1148,1294,1394,1654,2265,2966,3608,4201,4878,5449,7944,8889,9114,

%U 10508,11224,15706,17730,18564,21122,21806,21882,24462,24602,29384,35306

%N Numbers k such that 297*2^k-1 is prime.

%H Robert Price, <a href="/A050907/b050907.txt">Table of n, a(n) for n = 1..61</a>

%H Ray Ballinger and Wilfrid Keller, <a href="http://www.prothsearch.com/riesel1.html">List of primes k.2^n + 1 for k < 300</a>

%H Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k.2^n - 1 for k < 300</a>

%H Kosmaj, <a href="http://www.15k.org/riesellist.html">Riesel list k<300</a>.

%H <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime</a>

%p select(n->isprime(297*2^n-1),[$1..1000]); # _Muniru A Asiru_, Dec 30 2018

%t Select[Range[1000], PrimeQ[297*2^# - 1] & ] (* _Robert Price_, Dec 30 2018 *)

%o (PARI) is(n)=ispseudoprime(297*2^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K hard,nonn

%O 1,2

%A _N. J. A. Sloane_, Dec 29 1999

%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

%E a(49)-a(61) from the Wilfrid Keller link by _Robert Price_, Dec 30 2018