A032476 Numbers k such that 199*2^k+1 is prime.

2, 14, 18, 126, 134, 854, 1302, 22562, 42078, 44702, 44942, 60738, 267614

Offset

1,1

Links

Table of n, a(n) for n=1..13.

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[199*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)

Prog

(PARI) is(n)=ispseudoprime(199*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A212048 A322955 A266388 * A274062 A059205 A298002

Adjacent sequences: A032473 A032474 A032475 * A032477 A032478 A032479

Keyword

nonn,more,hard

Author

N. J. A. Sloane.

Extensions

a(13) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018

Status

approved