A323043 - OEIS

%I #12 Dec 18 2024 16:35:58

%S 4,6,16,24,30,36,40,52,60,78,132,204,352,556,1936,4876,5278,6450,6546,

%T 9498,10878,13012,22356,24498,28768,29952,41050,46242,56874,61414,

%U 74148,81306,118090,134056,391200,598342,825972,1293028,2598796,3859450

%N Numbers k such that 397*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[397*2^# + 1] &] (* _Robert Price_, Jan 03 2019 *)

%K nonn,more,hard

%O 1,1

%A _Robert Price_, Jan 03 2019

%E a(39) from _Jeppe Stig Nielsen_, Jan 04 2020

%E a(40) from _Jeppe Stig Nielsen_, Dec 18 2024