A053365 - OEIS

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A053365

Numbers k such that 297*2^k + 1 is prime.

3, 6, 14, 15, 20, 27, 38, 123, 276, 327, 380, 411, 546, 819, 1155, 1274, 1800, 1875, 3135, 3411, 7514, 9446, 12615, 23400, 23564, 99344, 108258, 148988, 153818, 157623, 306596, 622800, 2660048

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..33.

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[297*2^# + 1] &] (* G. C. Greubel, May 25 2018 *)

PROG

(PARI) is(n)=ispseudoprime(297*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

(Magma) [n: n in [1..3000] | IsPrime(297*2^n+1)]; // G. C. Greubel, May 25 2018

CROSSREFS

Sequence in context: A359669 A322183 A295292 * A101034 A342103 A084168

Adjacent sequences: A053362 A053363 A053364 * A053366 A053367 A053368

KEYWORD

hard,nonn,more

AUTHOR

N. J. A. Sloane, Dec 29 1999

EXTENSIONS

a(28)-a(32) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 22 2018

a(33) from Jeppe Stig Nielsen, Mar 12 2020

STATUS

approved