A032403 - OEIS

%I #32 Apr 04 2020 19:59:13

%S 3,7,23,27,291,303,311,479,567,3087,18459,33575,43123,58291,155587,

%T 173007,414531,1220391,1337019,2081775,2401731

%N Numbers k such that 107*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>

%o (PARI) is(n)=ispseudoprime(107*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,hard

%O 1,1

%A _James R. Buddenhagen_

%E Extended by _Hugo Pfoertner_, Jul 02 2003

%E a(16)-a(20) from http://www.prothsearch.com/riesel1.html by _Robert Price_, Dec 14 2018

%E a(21) from _Jeppe Stig Nielsen_, Apr 04 2020