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 A102982 Numbers n such that 4*10^n + R_n + 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n. 1
 1, 4, 84, 165, 274, 513, 3372, 4177, 4318, 10579, 17221, 19672, 20065, 36646, 40191, 55359, 86230 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Also numbers n such that (37*10^n+53)/9 is prime. a(18) > 10^5. - Robert Price, May 10 2015 LINKS Makoto Kamada, Prime numbers of the form 411...117. FORMULA a(n) = A101717(n) + 1. MATHEMATICA Do[ If[ PrimeQ[(37*10^n + 53)/9], Print[n]], {n, 0, 10000}] CROSSREFS Cf. A002275, A101717. Sequence in context: A333458 A119514 A316490 * A231741 A172138 A282588 Adjacent sequences:  A102979 A102980 A102981 * A102983 A102984 A102985 KEYWORD more,nonn AUTHOR Robert G. Wilson v, Dec 21 2004 EXTENSIONS Addition of a(10)-a(13) from Kamada data by Robert Price, Dec 13 2010 a(14)-a(15) from Erik Branger May 01 2013 by Ray Chandler, Aug 16 2013 a(16)-a(17) from Robert Price, May 10 2015 STATUS approved

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Last modified November 26 12:37 EST 2020. Contains 338639 sequences. (Running on oeis4.)