The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #24 Mar 12 2020 17:49:21
%S 1,13,6253,23313,77289,135033,349149,604585,1099741,1673881,2199301,
%T 2578197,2729905
%N Numbers k such that 173*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 Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k.2^n - 1 for k < 300</a>
%t Select[Range[1000], PrimeQ[173*2^# + 1] & ] (* _Robert Price_, Dec 18 2018 *)
%o (PARI) is(n)=ispseudoprime(173*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%K nonn,hard,more
%O 1,2
%A _N. J. A. Sloane_.
%E a(6)-a(10) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 18 2018
%E a(11)-a(13) from _Jeppe Stig Nielsen_, Mar 12 2020