

A103087


Numbers n such that 8*10^n + 6*R_n  3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.


1



0, 1, 2, 3, 13, 19, 62, 80, 126, 168, 195, 309, 410, 481, 608, 741, 879, 1176, 2688, 6236, 16294, 17317, 31574, 34861, 35392, 48726
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OFFSET

1,3


COMMENTS

Also numbers n such that (26*10^n11)/3 is prime.
a(27) > 10^5.  Robert Price, Oct 25 2015


LINKS

Table of n, a(n) for n=1..26.
Makoto Kamada, Prime numbers of the form 866...663.
Index entries for primes involving repunits.


FORMULA

a(n) = A101074(n1) + 1, for n>1.


MATHEMATICA

Do[ If[ PrimeQ[(26*10^n  11)/3], Print[n]], {n, 0, 10000}]


CROSSREFS

Cf. A002275, A101074.
Sequence in context: A194598 A080359 A193507 * A302485 A135118 A274905
Adjacent sequences: A103084 A103085 A103086 * A103088 A103089 A103090


KEYWORD

more,nonn


AUTHOR

Robert G. Wilson v, Jan 19 2005


EXTENSIONS

a(21)a(22) from Kamada data by Robert Price, Dec 14 2010
a(23)a(26) from Erik Branger May 01 2013 by Ray Chandler, Aug 16 2013
Inserted a(1)=0 by Robert Price, Oct 25 2015


STATUS

approved



