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%I #36 Feb 25 2024 05:59:45
%S 4,12,48,88,168,3328,172428,285652,4749928
%N Numbers k such that 61*2^k + 1 is prime.
%H Ray Ballinger, <a href="http://www.prothsearch.com/index.html">Proth Search Page</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 Prime Pages, <a href="https://t5k.org/primes/search.php?Description=%5E61*2%5E%25%2B1%24&OnList=all&Style=HTML">Database Search Output</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>
%o (Magma) [n: n in [1..3500] |IsPrime(61*2^n + 1)] // _Vincenzo Librandi_, Nov 20 2010
%o (PARI) is(n)=ispseudoprime(61*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%K nonn,hard
%O 1,1
%A _James R. Buddenhagen_
%E More terms (from http://web.archive.org/web/20161028080239/http://www.prothsearch.net/riesel.html), _Joerg Arndt_, Apr 07 2013
%E a(9) communicated by _Jeppe Stig Nielsen_, Feb 25 2024
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