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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
2, 260, 417, 953, 2138, 2969, 3045, 11777, 23648 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also numbers n such that (55*10^n+71)/9 is prime.

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

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Last modified August 28 03:16 EDT 2015. Contains 261112 sequences.