A053354 Numbers k such that 275*2^k + 1 is prime.

7, 15, 21, 25, 27, 69, 71, 105, 207, 285, 611, 635, 647, 969, 1127, 1159, 2407, 2529, 3517, 3577, 6275, 6729, 7919, 8809, 9375, 27369, 31657, 44149, 58579, 59355, 274255, 285435, 350949, 485505, 821221, 834297

Offset

1,1

Links

Table of n, a(n) for n=1..36.

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

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

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

Mathematica

Select[Range[5*10^3], PrimeQ[275*2^# + 1] &] (* G. C. Greubel, May 24 2018 *)

Prog

(PARI) is(n)=ispseudoprime(275*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [n: n in [1..300] | IsPrime(275*2^n+1)];  // G. C. Greubel, May 24 2018

Crossrefs

Sequence in context: A151971 A014659 A179676 * A346197 A274700 A022552

Adjacent sequences: A053351 A053352 A053353 * A053355 A053356 A053357

Keyword

hard,nonn,more

Author

N. J. A. Sloane, Dec 29 1999

Extensions

a(31)-a(36) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018

Status

approved