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A102936 Numbers k such that 10^k + 5*R_k - 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k. 1
1, 3, 6, 15, 70, 76, 13024, 60346 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Also numbers k such that (14*10^k - 23)/9 is prime.
a(9) > 10^5. - Robert Price, Apr 10 2015
LINKS
FORMULA
a(n) = A102019(n) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(14*10^n - 23)/9], Print[n]], {n, 0, 10000}]
CROSSREFS
Sequence in context: A241269 A102356 A208662 * A009192 A013273 A013277
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Dec 16 2004
EXTENSIONS
Addition of a(7) from Kamada data by Robert Price, Dec 13 2010
a(8) from Robert Price, Apr 10 2015
STATUS
approved

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Last modified March 29 06:13 EDT 2024. Contains 371265 sequences. (Running on oeis4.)