A050547 Numbers n such that 43*2^n-1 is prime.

7, 31, 67, 251, 767, 1171, 1643, 25423, 38863, 50867, 60391, 100303, 286171, 399767

Offset

1,1

Links

Table of n, a(n) for n=1..14.

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

Kosmaj, Riesel list k<300.

Prog

(PARI) is(n)=ispseudoprime(43*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A032371, 43*2^n+1 is prime.

Sequence in context: A031388 A163354 A105428 * A157914 A090684 A033199

Adjacent sequences: A050544 A050545 A050546 * A050548 A050549 A050550

Keyword

hard,nonn

Author

N. J. A. Sloane, Dec 29 1999

Extensions

More terms from Hugo Pfoertner, Oct 13 2004

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Status

approved