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Numbers k such that 143*2^k+1 is prime.
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%I #24 Dec 20 2018 14:03:04

%S 53,77,293,333,393,809,825,20973,85349,270285,459093,699189,859769,

%T 1650689

%N Numbers k such that 143*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 Y. Gallot, <a href="http://www.utm.edu/research/primes/programs/gallot/index.html">Proth.exe: Windows Program for Finding Large Primes</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[143*2^# + 1] & ] (* _Robert Price_, Dec 18 2018 *)

%o (PARI) is(n)=ispseudoprime(143*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,hard,more

%O 1,1

%A _James R. Buddenhagen_

%E a(10)-a(14) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 18 2018