%I #8 Dec 18 2024 19:08:53
%S 4,20,28,40,88,92,328,1052,1420,2888,3944,5888,22544,154912,716668,
%T 2971600,3693728
%N Numbers k such that 391*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>
%t Select[Range[1000], PrimeQ[391*2^# + 1] &] (* _Robert Price_, Jan 03 2019 *)
%K nonn,more,hard
%O 1,1
%A _Robert Price_, Jan 03 2019
%E a(16)-a(17) from _Jeppe Stig Nielsen_, Dec 18 2024