login
A306647
Numbers k such that 2*k^A006530(k) + 1 is prime.
0
1, 6, 9, 12, 14, 21, 27, 30, 72, 92, 96, 126, 150, 162, 165, 192, 225, 242, 251, 261, 341, 345, 384, 392, 420, 455, 462, 500, 540, 629, 684, 704, 779, 800, 825, 990, 1350, 1386, 1404, 1482, 1512, 1625, 1725, 1808, 2001, 2028, 2115, 2184, 2322, 2499, 2835
OFFSET
1,2
COMMENTS
All prime members are also in A110932, but the only known example is 251.
PROG
(PARI) print1(1, ", "); (gpf(k)=t=factor(k); t[matsize(t)[1], 1]); for(k=2, +oo, ispseudoprime(2*k^gpf(k)+1)&&print1(k, ", "))
CROSSREFS
Sequence in context: A267918 A330703 A262828 * A189728 A214777 A239310
KEYWORD
nonn
AUTHOR
Jeppe Stig Nielsen, Mar 03 2019
STATUS
approved