A032410 Numbers k such that 121*2^k+1 is prime.

8, 12, 44, 84, 96, 228, 264, 320, 732, 788, 1808, 7928, 12264, 37784, 59196, 91112, 112208, 168716, 251184, 264632, 272052, 513020, 636564, 674360

Offset

1,1

Comments

9584444 is also a term (cf. PrimeGrid, 2020). - Felix Fröhlich, Dec 10 2020

Links

Table of n, a(n) for n=1..24.

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

PrimeGrid, Announcement of 9584444, 2020.

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Mathematica

Select[Range[1000], PrimeQ[121*2^# + 1] & ] (* Robert Price, Dec 17 2018 *)

Prog

(PARI) is(n)=ispseudoprime(121*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A050586.

Sequence in context: A281663 A092179 A269726 * A077101 A229497 A009926

Adjacent sequences: A032407 A032408 A032409 * A032411 A032412 A032413

Keyword

nonn,hard,more

Author

James R. Buddenhagen

Extensions

Extended by Hugo Pfoertner, Jul 02 2003

a(20)-a(24) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 17 2018

Status

approved