A032461 - OEIS

%I #25 Apr 04 2020 19:21:01

%S 2,14,26,158,282,298,406,522,534,1050,1470,1478,1614,1970,2570,5054,

%T 5166,6238,9614,14026,49602,63686,70110,76934,109666,167734,223590,

%U 602070,801578,1327114,1635086,2545526

%N Numbers k such that 169*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>

%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[169*2^# + 1] & ] (* _Robert Price_, Dec 18 2018 *)

%o (PARI) is(n)=ispseudoprime(169*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,hard,more

%O 1,1

%A _N. J. A. Sloane_.

%E a(23)-a(31) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 18 2018

%E a(32) from _Jeppe Stig Nielsen_, Apr 04 2020