A053355 Numbers k such that 277*2^k + 1 is prime.

2, 6, 8, 18, 20, 22, 36, 62, 108, 120, 162, 180, 222, 450, 530, 706, 1028, 1200, 1296, 1362, 2280, 3788, 7130, 8082, 8150, 10226, 10302, 11578, 48426, 57890, 73890, 139346, 201378, 225322, 1134740, 1584740, 1634878, 1728302, 1880022, 2340182, 5185268

Offset

1,1

Links

Table of n, a(n) for n=1..41.

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[277*2^# + 1] &] (* G. C. Greubel, May 24 2018 *)

Prog

(PARI) is(n)=ispseudoprime(277*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [n: n in [1..300] | IsPrime(277*2^n+1)];  // G. C. Greubel, May 24 2018

Crossrefs

Sequence in context: A183212 A360264 A325686 * A233572 A370864 A005823

Adjacent sequences: A053352 A053353 A053354 * A053356 A053357 A053358

Keyword

hard,nonn,more,changed

Author

N. J. A. Sloane, Dec 29 1999

Extensions

a(31)-a(39) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018

a(40) from Jeppe Stig Nielsen, Apr 04 2020

a(41) from Jeppe Stig Nielsen, Dec 21 2024

Status

approved