login
This site is supported by donations to The OEIS Foundation.

 

Logo

Many excellent designs for a new banner were submitted. We will use the best of them in rotation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A100473 Numbers n such that 9*10^n + R_n + 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n. 2
1, 17, 23, 73, 131, 473, 685, 701, 1909, 3029, 3473, 4193, 9931 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Also numbers n such that (82*10^n+53)/9 is a prime.

Some of the larger entries may only correspond to probable primes.

LINKS

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

Makoto Kamada, Factorizations of 911...117.

Index entries for primes involving repunits.

EXAMPLE

n = 1, 17, so that 97 and 911111111111111117 are primes.

MATHEMATICA

Do[ If[ PrimeQ[(82*10^n + 53)/9], Print[n]], {n, 0, 10000}] (from Robert G. Wilson v Jan 19 2005)

CROSSREFS

Sequence in context: A039319 A043142 A043922 * A060252 A127924 A108260

Adjacent sequences:  A100470 A100471 A100472 * A100474 A100475 A100476

KEYWORD

more,nonn

AUTHOR

Julien Peter Benney (jpbenney(AT)ftml.net), Nov 21 2004

EXTENSIONS

a(8)- a(12) from Robert G. Wilson v, Jan 12 2005

a(13) from Robert G. Wilson v, Jan 12 2005

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified April 25 00:50 EDT 2014. Contains 240991 sequences.