A323114 - OEIS

%I #22 Mar 19 2023 02:31:15

%S 2,4,6,8,12,20,22,56,66,94,136,142,174,186,200,286,352,362,512,582,

%T 842,1056,1080,1144,1242,1810,4802,5106,6914,12982,16760,19958,20108,

%U 22194,23512,29636,42816,66178,70624,81390,129958,184046,278876,343432,396612

%N Numbers k such that 427*2^k+1 is prime.

%H Jeppe Stig Nielsen, <a href="/A323114/b323114.txt">Table of n, a(n) for n = 1..57</a> (terms n = 1..54 from Robert Price)

%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(k->isprime(427*2^k+1),[$1..1000]); # _Muniru A Asiru_, Jan 05 2019

%t Select[Range[1000], PrimeQ[427*2^# + 1] &]

%o (Python)

%o from sympy.ntheory.primetest import isprime

%o for n in range(1,1000):

%o     if isprime(427*2**n+1):

%o         print(n, end=', ') # _Stefano Spezia_, Jan 05 2019

%K nonn,hard

%O 1,1

%A _Robert Price_, Jan 04 2019