A032464 Numbers k such that 175*2^k+1 is prime.

2, 4, 16, 32, 34, 36, 52, 56, 82, 88, 96, 146, 268, 284, 404, 856, 1652, 3254, 3848, 4364, 5034, 9666, 11542, 14068, 18086, 19634, 21614, 23032, 45736, 57676, 62642, 97288, 111692, 113488, 133908, 242514, 502646, 695576, 814158, 862436, 1022634, 1962288

Offset

1,1

Links

Table of n, a(n) for n=1..42.

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[175*2^# + 1] & ] (* Robert Price, Dec 18 2018 *)

Prog

(PARI) is(n)=ispseudoprime(175*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A173746 A095803 A036345 * A171381 A334083 A274497

Adjacent sequences: A032461 A032462 A032463 * A032465 A032466 A032467

Keyword

nonn,hard

Author

N. J. A. Sloane.

Extensions

a(33)-a(42) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 18 2018

Status

approved