A053356 - OEIS

A053356

Numbers k such that 279*2^k + 1 is prime.

2, 5, 10, 67, 70, 185, 218, 254, 530, 539, 587, 767, 806, 1142, 1169, 2098, 3035, 4310, 8909, 14150, 15461, 15778, 15962, 16711, 17819, 41915, 78578, 90047, 274202, 335351, 430342, 888782, 1465658, 1526518, 2079167

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..35.

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[279*2^# + 1] &] (* G. C. Greubel, May 24 2018 *)

PROG

(PARI) is(n)=ispseudoprime(279*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

(Magma) [n: n in [1..300] | IsPrime(279*2^n+1)]; // G. C. Greubel, May 24 2018

CROSSREFS

Sequence in context: A140304 A183451 A018549 * A018584 A296308 A018603

Adjacent sequences: A053353 A053354 A053355 * A053357 A053358 A053359

KEYWORD

hard,nonn,more

AUTHOR

N. J. A. Sloane, Dec 29 1999

EXTENSIONS

a(27)-a(34) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018

a(35) from Jeppe Stig Nielsen, May 30 2020

STATUS

approved