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 A103012 Numbers n such that 5*10^n + 3*R_n + 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n. 1
 0, 1, 47, 69, 99, 575, 715, 2179, 10541 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Also numbers n such that (16*10^n+17)/3 is prime. a(10) > 10^5. - Robert Price, Sep 08 2015 LINKS Makoto Kamada, Prime numbers of the form 533...339. FORMULA a(n) = A101577(n-1) + 1 for n>1. EXAMPLE For n=0, (16*10^n+17)/3=11 which is prime, so 0 is in the sequence. MATHEMATICA Do[ If[ PrimeQ[(16*10^n + 17)/3], Print[n]], {n, 0, 10000}] CROSSREFS Cf. A002275, A101577. Sequence in context: A245745 A023331 A187923 * A166958 A112056 A033231 Adjacent sequences:  A103009 A103010 A103011 * A103013 A103014 A103015 KEYWORD nonn AUTHOR Robert G. Wilson v, Jan 18 2005 EXTENSIONS a(9) from Kamada data by Robert Price, Dec 14 2010 Inserted a(1)=0 by Robert Price, Sep 08 2015 STATUS approved

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