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%I #13 Dec 18 2024 16:33:46
%S 1,2,4,8,10,14,32,43,46,58,80,163,184,227,262,361,592,602,623,638,
%T 2287,2680,3674,11221,12278,12556,12763,15412,21472,49118,57040,64825,
%U 121262,127495,300604,572623,769828,904000,1693765,2099716,3757192
%N Numbers k such that 405*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="http://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>
%p select(k->isprime(405*2^k+1),[$1..1000]); # _Muniru A Asiru_, Jan 04 2019
%t Select[Range[1000], PrimeQ[405*2^# + 1] &]
%K nonn,more,hard
%O 1,2
%A _Robert Price_, Jan 04 2019
%E a(40) from _Jeppe Stig Nielsen_, May 30 2020
%E a(41) from _Jeppe Stig Nielsen_, Dec 18 2024