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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A103104 Numbers n such that 9*10^n + 6*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n. 1
1, 2, 4, 7, 13, 28, 58, 86, 92, 108, 1408, 1486, 1712, 2674, 3880, 5536, 7588, 7650, 10558, 15532, 17959, 37180, 93082 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Also numbers n such that (29*10^n+1)/3 is prime.

a(24) > 10^5. - Robert Price, Nov 12 2015

LINKS

Table of n, a(n) for n=1..23.

Makoto Kamada, Prime numbers of the form 966...667.

Index entries for primes involving repunits.

FORMULA

a(n) = A101013(n) + 1.

MATHEMATICA

Do[ If[ PrimeQ[(29*10^n + 1)/3], Print[n]], {n, 0, 10000}]

CROSSREFS

Cf. A002275, A101013.

Sequence in context: A112740 A265580 A136408 * A103480 A024826 A102114

Adjacent sequences:  A103101 A103102 A103103 * A103105 A103106 A103107

KEYWORD

more,nonn

AUTHOR

Robert G. Wilson v, Jan 19 2005

EXTENSIONS

a(19)-a(21) from Kamada data by Robert Price, Dec 14 2010

a(22) from Erik Branger May 01 2013 by Ray Chandler, Aug 17 2013

a(23) from Robert Price, Nov 12 2015

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.

License Agreements, Terms of Use, Privacy Policy .

Last modified September 29 14:56 EDT 2016. Contains 276614 sequences.