A032415 Numbers k such that 131*2^k+1 is prime.

1, 3, 9, 13, 19, 21, 25, 51, 55, 97, 153, 165, 199, 261, 285, 361, 373, 465, 475, 529, 765, 2065, 3553, 4377, 5421, 6859, 7371, 11815, 21657, 29089, 31843, 33549, 35017, 50169, 102321, 114073, 118321, 218697, 261999, 278175, 430231, 470245, 1494099, 4227493

Offset

1,2

Links

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..47

Ray Ballinger, Proth Search Page

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

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

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[1000], PrimeQ[131*2^# + 1] & ] (* Robert Price, Dec 17 2018 *)

Prog

(PARI) is(n)=ispseudoprime(131*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [n: n in [1..6000] | IsPrime(131*2^n+1)]; // Vincenzo Librandi, Dec 18 2018

Crossrefs

Sequence in context: A298870 A095234 A240240 * A268044 A190745 A075318

Adjacent sequences: A032412 A032413 A032414 * A032416 A032417 A032418

Keyword

nonn

Author

James R. Buddenhagen

Extensions

Extended by Hugo Pfoertner, Jul 02 2003

a(38)-a(43) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 17 2018

a(44) from Jeppe Stig Nielsen, Dec 23 2024

Status

approved