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

Offset

1,1

Links

Table of n, a(n) for n=1..40.

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

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

Status

approved