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

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A110285 Numbers n such that n*10^n + n - 1 is prime. 0
 168, 760, 2154, 9172 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Not proved, only Fermat and Lucas PRPs. Next term is greater than 12000. Concerning primes of the form n * 10^n + n + 1, only n=42 yields one for all n up to 7700. LINKS PROG (PARI) is(n)=ispseudoprime(n*10^n+n-1) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Sequence in context: A234816 A245868 A251461 * A302887 A235071 A235064 Adjacent sequences: A110282 A110283 A110284 * A110286 A110287 A110288 KEYWORD more,nonn AUTHOR Jason Earls, Sep 07 2005 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.

Last modified December 5 15:27 EST 2022. Contains 358588 sequences. (Running on oeis4.)