login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A050616 Numbers k such that 149*2^k-1 is prime. 0
4, 16, 48, 60, 240, 256, 304, 2644, 3720, 25132, 39472, 212460, 592968 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms appear to be multiples of four. - Robert Price, Dec 23 2018

LINKS

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

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.

MATHEMATICA

Select[Range[1000], PrimeQ[149*2^# - 1] & ] (* Robert Price, Dec 23 2018 *)

PROG

(PARI) is(n)=ispseudoprime(149*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A174836 A244252 A308592 * A297160 A006009 A261977

Adjacent sequences:  A050613 A050614 A050615 * A050617 A050618 A050619

KEYWORD

hard,nonn,more

AUTHOR

N. J. A. Sloane, Dec 29 1999

EXTENSIONS

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 7 11:38 EDT 2022. Contains 355985 sequences. (Running on oeis4.)