login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A050885
Numbers n such that 253*2^n-1 is prime.
0
71, 1007, 27623, 1722623
(
list
;
graph
;
refs
;
listen
;
history
;
text
;
internal format
)
OFFSET
1,1
LINKS
Table of n, a(n) for n=1..4.
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(253*2^n-1) \\
Charles R Greathouse IV
, Jun 13 2017
CROSSREFS
Sequence in context:
A253683
A210699
A346023
*
A200909
A175215
A231414
Adjacent sequences:
A050882
A050883
A050884
*
A050886
A050887
A050888
KEYWORD
hard
,
nonn
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 April 25 11:39 EDT 2024. Contains 371969 sequences. (Running on oeis4.)