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Numbers k such that 229*2^k+1 is prime.
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%I #26 Aug 06 2024 21:16:03

%S 6,82,186,334,690,838,1146,1482,2262,5118,5398,6294,9322,15270,15930,

%T 28134,34926,47878,52986,217234,370086,484018,786034,1118806,1818078,

%U 1956294

%N Numbers k such that 229*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[229*2^# + 1] & ] (* _Robert Price_, Dec 19 2018 *)

%o (PARI) is(n)=ispseudoprime(229*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,hard,more

%O 1,1

%A _N. J. A. Sloane_.

%E a(20)-a(26) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 19 2018