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 A093176 Primes of the form 70*R_n + 1, where R_n is the repunit (A002275) of length n. 8
 71, 7777777777771, 77777777777777777771, 77777777777777777777771, 7777777777777777777777777777771, 7777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777771 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes of the form (7*10^n - 61)/9. - Vincenzo Librandi, Nov 16 2010 LINKS Makoto Kamada, Prime numbers of the form 77...771. FORMULA a(n) = (70*10^A056688(n) - 61)/9 = (7*10^A099419(n) - 61)/9. CROSSREFS Cf. A002275, A056688 (corresponding n), A099419. Sequence in context: A144242 A144360 A230378 * A057384 A240254 A228095 Adjacent sequences:  A093173 A093174 A093175 * A093177 A093178 A093179 KEYWORD nonn AUTHOR Rick L. Shepherd, Mar 27 2004 EXTENSIONS Edited by Ray Chandler, Mar 06 2012 STATUS approved

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Last modified July 22 14:40 EDT 2019. Contains 325222 sequences. (Running on oeis4.)