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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. a(10) > 10^5. - Robert Price, Sep 08 2015 LINKS Makoto Kamada, Prime numbers of the form 611...119. 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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