A032462 Numbers k such that 171*2^k+1 is prime.

8, 9, 24, 32, 71, 117, 141, 144, 369, 393, 575, 837, 921, 1007, 3825, 3837, 18813, 21731, 25233, 36261, 57104, 128301, 299840, 404379, 714200, 717731, 910544, 1061853, 1658303

Offset

1,1

Links

Table of n, a(n) for n=1..29.

Ray Ballinger, Proth Search Page

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[1000], PrimeQ[171*2^# + 1] & ] (* Robert Price, Dec 18 2018 *)

Prog

(PARI) is(n)=ispseudoprime(171*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A304600 A278076 A081351 * A077599 A109097 A335770

Adjacent sequences: A032459 A032460 A032461 * A032463 A032464 A032465

Keyword

nonn,hard,more

Author

N. J. A. Sloane.

Extensions

a(22)-a(29) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 18 2018

Status

approved