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Numbers k such that 341*2^k+1 is prime.
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%I #10 Dec 20 2024 09:56:23

%S 1,3,7,19,21,33,43,99,183,235,499,579,1137,1225,1941,1987,2409,3285,

%T 9093,9121,11043,14997,17919,31543,57163,83595,127915,129199,220651,

%U 384961,1255881,1325277,1728697,3300789,3686613,3938565

%N Numbers k such that 341*2^k+1 is prime.

%H Ray Ballinger, <a href="http://www.prothsearch.com/index.html">Proth Search Page</a>

%H Ray Ballinger and Wilfrid Keller, <a href="http://www.prothsearch.com/riesel1a.html">List of primes k.2^n + 1 for 300 < k < 600</a>

%H Y. Gallot, <a href="http://www.utm.edu/research/primes/programs/gallot/index.html">Proth.exe: Windows Program for Finding Large Primes</a>

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

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ProthPrime.html">Proth Prime</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(341*2^n+1),[$1..1000]); # _Muniru A Asiru_, Dec 31 2018

%t Select[Range[1000], PrimeQ[341*2^# + 1] &] (* _Robert Price_, Dec 31 2018 *)

%Y Cf. A002255, A050527.

%K nonn,more,hard

%O 1,2

%A _Robert Price_, Dec 31 2018

%E a(34)-a(36) from _Jeppe Stig Nielsen_, Dec 20 2024