%I #32 Dec 21 2024 09:47:26
%S 1,2,3,9,13,14,17,21,22,25,27,51,58,99,138,197,325,386,413,475,529,
%T 771,826,1114,1981,2249,2333,2673,3171,3534,5214,7197,7275,9307,16321,
%U 16851,17993,18753,19825,26165,27477,27997,33253,64537,64694,71259,134666
%N Numbers k such that 219*2^k+1 is prime.
%H Jeppe Stig Nielsen, <a href="/A032486/b032486.txt">Table of n, a(n) for n = 1..62</a> (terms n = 1..58 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/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[219*2^# + 1] & ] (* _Robert Price_, Dec 19 2018 *)
%o (PARI) is(n)=ispseudoprime(219*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%K nonn,hard
%O 1,2
%A _N. J. A. Sloane_.
%E a(47)-a(58) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 19 2018