A322955 Numbers k such that 325*2^k+1 is prime.

2, 14, 18, 32, 42, 72, 144, 174, 282, 318, 828, 1338, 2154, 2750, 4034, 9858, 13692, 49052, 63522, 86784, 117162, 126014, 273090, 302574, 413862, 901902, 3231474, 4097700

Offset: 1

Author

Robert Price, Dec 31 2018

Keywords

• nonn
• more
• hard

Links

• 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

Crossrefs

Cf. A002255, A050527.

Programs

Maple

select(n->isprime(325*2^n+1),[$1..1000]); # Muniru A Asiru, Dec 31 2018

Mathematica

Select[Range[1000], PrimeQ[325*2^# + 1] &] (* Robert Price, Dec 31 2018 *)

Extensions

a(27)-a(28) from Jeppe Stig Nielsen, Dec 20 2024