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Numbers k such that 449*2^k+1 is prime.
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%I #6 Feb 16 2025 08:33:57

%S 3,5,17,25,53,65,75,93,227,263,265,455,627,805,1187,1253,3345,6377,

%T 11465,11977,12317,25097,34683,42097,113387,139585,186287,214323,

%U 1093035

%N Numbers k such that 449*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/riesel1a.html">List of primes k.2^n + 1 for 300 < k < 600</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 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ProthPrime.html">Proth Prime</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[449*2^# + 1] &]

%K nonn,more,hard,changed

%O 1,1

%A _Robert Price_, Jan 06 2019