%I #20 Jan 05 2025 19:51:35
%S 6,14,18,48,60,80,296,354,428,738,2118,2856,2960,6992,25610,26520,
%T 27354,36804,41616,48684,52236,58400
%N Numbers k such that 2047*2^k+1 is prime.
%H E. L. Blanton, Jr., S. P. Hurd and J. S. McCranie, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/30-4/blanton.pdf">On a digraph defined by squaring modulo n</a>, Fibonacci Quart. 30 (Nov. 1992), 322-333.
%o (PARI) is(n)=ispseudoprime(2047*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%K nonn,hard,more
%O 1,1
%A _Jud McCranie_
%E The term 738 was omitted from the reference. 4 more terms Jun 15 1998.
%E a(19)-a(22) from _Michael S. Branicky_, Jul 12 2023