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A102999 Numbers n such that 4*10^n + 8*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n. 1
0, 1, 2, 7, 14, 25, 116, 427, 595, 637, 776, 1706, 16628, 55558 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Also numbers n such that (44*10^n-17)/9 is prime.
a(15) > 10^5. - Robert Price, Jun 05 2015
LINKS
FORMULA
a(n) = A101736(n) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(44*10^n - 17)/9], Print[n]], {n, 0, 10000}]
CROSSREFS
Sequence in context: A088207 A194111 A343859 * A225277 A367954 A333644
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Jan 17 2005
EXTENSIONS
Addition of a(13) from Kamada data by Robert Price, Dec 13 2010
a(14) from Robert Price, Jun 05 2015
Prepended a(1) = 0 by Robert Price, Jun 05 2015
STATUS
approved

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Last modified March 28 07:48 EDT 2024. Contains 371235 sequences. (Running on oeis4.)