A322949 Numbers k such that 315*2^k+1 is prime.

1, 3, 6, 9, 20, 22, 27, 32, 72, 97, 99, 104, 107, 120, 140, 142, 151, 180, 304, 305, 342, 440, 489, 521, 635, 665, 673, 767, 876, 1040, 1313, 1359, 1764, 2032, 2224, 2280, 2783, 2832, 2875, 5256, 8225, 10297, 11124, 12124, 17552, 18592, 24435, 30704, 37467

Offset: 1

Author

Robert Price, Dec 31 2018

Keywords

• nonn
• hard

Links

• Jeppe Stig Nielsen, Table of n, a(n) for n = 1..77 (terms n = 1..74 from Robert Price)
• 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

Mathematica

Select[Range[1000], PrimeQ[315*2^# + 1] &] (* Robert Price, Dec 31 2018 *)