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%I #30 Jan 18 2020 11:00:50
%S 1,2,3,6,7,10,14,15,23,34,43,50,59,79,111,114,127,142,143,145,154,159,
%T 181,187,342,474,490,510,766,789,843,1062,1370,1711,2070,5007,5250,
%U 5394,8483,8587,8871,8929,9682,11146,12402,13587,14226,15143,20719,21262
%N Numbers k such that 249*2^k+1 is prime.
%H Jeppe Stig Nielsen, <a href="/A032501/b032501.txt">Table of n, a(n) for n = 1..81</a> (terms n = 1..78 from Robert Price)
%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 Ray Ballinger, <a href="http://www.prothsearch.com/index.html">Proth Search Page</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[249*2^# + 1] & ] (* _Robert Price_, Dec 20 2018 *)
%o (PARI) is(n)=ispseudoprime(249*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%K nonn,hard
%O 1,2
%A _N. J. A. Sloane_
%E a(50)-a(78) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 20 2018
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