

A102994


Numbers n such that 4*10^n + 6*R_n  5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.


3



1, 2, 7, 9, 14, 24, 45, 49, 73, 74, 232, 338, 397, 504, 1063, 2817, 5305, 16768, 27060
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OFFSET

1,2


COMMENTS

Also numbers n such that (14*10^n17)/3 is prime.
a(20) > 10^5.  Robert Price, May 27 2015


LINKS

Table of n, a(n) for n=1..19.
Makoto Kamada, Prime numbers of the form 466...661.
Index entries for primes involving repunits.


FORMULA

a(n) = A101729(n) + 1.


MATHEMATICA

Do[ If[ PrimeQ[(14*10^n  17)/3], Print[n]], {n, 0, 10000}]


CROSSREFS

Cf. A002275, A101729.
Sequence in context: A184400 A074244 A190565 * A226824 A168132 A211280
Adjacent sequences: A102991 A102992 A102993 * A102995 A102996 A102997


KEYWORD

more,nonn


AUTHOR

Robert G. Wilson v, Jan 17 2005


EXTENSIONS

Addition of a(18)a(19) from Kamada data by Robert Price, Dec 10 2010


STATUS

approved



