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!)
A093405 Primes of the form 80*R_k + 9, where R_k is the repunit (A002275) of length k. 0
89, 88888888888889, 88888888888888889, 88888888888888888888888888888888889 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Primes of the form (8*10^k + 1)/9. - Vincenzo Librandi, Jul 17 2012
LINKS
MATHEMATICA
Select[Table[(8*10^n+1)/9, {n, 1, 200}], PrimeQ] (* Vincenzo Librandi, Jul 17 2012
Select[Table[FromDigits[PadLeft[{9}, n, 8]], {n, 100}], PrimeQ] (* Harvey P. Dale, Dec 15 2023 *)
CROSSREFS
Cf. A056663 (corresponding k).
Sequence in context: A072314 A087538 A087341 * A348166 A221307 A058631
KEYWORD
nonn
AUTHOR
Rick L. Shepherd, Mar 28 2004
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 March 28 07:46 EDT 2024. Contains 371235 sequences. (Running on oeis4.)