A323040 Numbers k such that 391*2^k+1 is prime.

4, 20, 28, 40, 88, 92, 328, 1052, 1420, 2888, 3944, 5888, 22544, 154912, 716668, 2971600, 3693728

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Ray Ballinger, Proth Search Page

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for 300 < k < 600

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

Wilfrid Keller, List of primes k.2^n - 1 for k < 300

Eric Weisstein's World of Mathematics, Proth Prime

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Mathematica

Select[Range[1000], PrimeQ[391*2^# + 1] &] (* Robert Price, Jan 03 2019 *)

Crossrefs

Sequence in context: A097251 A202070 A198831 * A259755 A317249 A181433

Adjacent sequences: A323037 A323038 A323039 * A323041 A323042 A323043

Keyword

nonn,more,hard

Author

Robert Price, Jan 03 2019

Extensions

a(16)-a(17) from Jeppe Stig Nielsen, Dec 18 2024

Status

approved