

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
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OFFSET

1,2


COMMENTS

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


LINKS

Table of n, a(n) for n=1..22.
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: A256942 A112740 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


STATUS

approved



