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%I #36 Dec 20 2024 10:49:11
%S 3,6,14,15,20,27,38,123,276,327,380,411,546,819,1155,1274,1800,1875,
%T 3135,3411,7514,9446,12615,23400,23564,99344,108258,148988,153818,
%U 157623,306596,622800,2660048,3087543,3765140,4432947
%N Numbers k such that 297*2^k + 1 is prime.
%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 <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>
%t Select[Range[5*10^3], PrimeQ[297*2^# + 1] &] (* _G. C. Greubel_, May 25 2018 *)
%o (PARI) is(n)=ispseudoprime(297*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%o (Magma) [n: n in [1..3000] | IsPrime(297*2^n+1)]; // _G. C. Greubel_, May 25 2018
%K hard,nonn,more
%O 1,1
%A _N. J. A. Sloane_, Dec 29 1999
%E a(28)-a(32) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 22 2018
%E a(33) from _Jeppe Stig Nielsen_, Mar 12 2020
%E a(34)-a(36) from _Jeppe Stig Nielsen_, Dec 20 2024