login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Numbers k such that 145*2^k+1 is prime.
0

%I #31 Dec 23 2024 11:36:51

%S 6,16,28,70,76,250,276,312,562,636,1366,1552,1968,7000,7312,7548,7852,

%T 8116,16306,18868,20518,23676,27400,75858,207880,1233286,2621020,

%U 4327756

%N Numbers k such that 145*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/riesel1.html">List of primes k.2^n + 1 for k < 300</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 <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[145*2^# + 1] & ] (* _Robert Price_, Dec 18 2018 *)

%o (PARI) is(n)=ispseudoprime(145*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,more

%O 1,1

%A _James R. Buddenhagen_

%E a(25)-a(26) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 18 2018

%E a(27) from _Jeppe Stig Nielsen_, Mar 12 2020

%E a(28) from _Jeppe Stig Nielsen_, Dec 23 2024