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A103088 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
1, 3, 17, 19, 33, 39, 169, 453, 611, 883, 1473, 6511, 9647, 21593, 39991, 40157 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Also numbers n such that (26*10^n+7)/3 is prime.

LINKS

Table of n, a(n) for n=1..16.

Makoto Kamada, Prime numbers of the form 866...669.

Index entries for primes involving repunits.

FORMULA

a(n) = A101075(n) + 1.

MATHEMATICA

Do[ If[ PrimeQ[(26*10^n + 7)/3], Print[n]], {n, 0, 10000}]

CROSSREFS

Cf. A002275, A101075.

Sequence in context: A038886 A019342 A029473 * A226925 A259772 A082387

Adjacent sequences:  A103085 A103086 A103087 * A103089 A103090 A103091

KEYWORD

more,nonn

AUTHOR

Robert G. Wilson v, Jan 19 2005

EXTENSIONS

a(14)-a(16) from Kamada data by Robert Price, Dec 14 2010

STATUS

approved

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Last modified October 15 15:14 EDT 2019. Contains 328030 sequences. (Running on oeis4.)