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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

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 A250640

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 November 28 04:44 EST 2014. Contains 250286 sequences.