

A103029


Numbers n such that 6*10^n + R_n + 8 is prime, where R_n = 11...1 is the repunit (A002275) of length n.


1




OFFSET

1,1


COMMENTS

Also numbers n such that (55*10^n+71)/9 is prime.
a(10) > 10^5.  Robert Price, Sep 08 2015


LINKS

Table of n, a(n) for n=1..9.
Makoto Kamada, Prime numbers of the form 611...119.
Index entries for primes involving repunits.


FORMULA

a(n) = A101521(n) + 1.


MATHEMATICA

Do[ If[ PrimeQ[(55*10^n + 71)/9], Print[n]], {n, 0, 10000}]


CROSSREFS

Cf. A002275, A101521.
Sequence in context: A218435 A089663 A252708 * A122862 A236437 A137105
Adjacent sequences: A103026 A103027 A103028 * A103030 A103031 A103032


KEYWORD

more,nonn


AUTHOR

Robert G. Wilson v, Jan 18 2005


EXTENSIONS

Addition of a(8)a(9) from Kamada data by Robert Price, Dec 13 2010


STATUS

approved



