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 A040017 Unique period primes (no other prime has same period as 1/p) in order (periods are given in A051627). 17
 3, 11, 37, 101, 9091, 9901, 333667, 909091, 99990001, 999999000001, 9999999900000001, 909090909090909091, 1111111111111111111, 11111111111111111111111, 900900900900990990990991, 909090909090909090909090909091 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES J.-P. Delahaye, Merveilleux nombres premiers ("Amazing primes"), p. 324, Pour la Science Paris 2000. LINKS Robert G. Wilson v, Table of n, a(n) for n = 1..46 Chris Caldwell, The Prime Glossary, Unique prime C. K. Caldwell, "Top Twenty" page, Unique Chris K. Caldwell, Harvey Dubner, Unique-Period Primes, J. Recreational Math., 29:1 (1998) 43--48. Eric Weisstein's World of Mathematics, Unique Prime Wikipedia, Unique prime EXAMPLE The decimal expansion of 1/101 is 0.00990099..., having a period of 4 and it is the only prime with that period. MATHEMATICA lst = {}; Do[c = Cyclotomic[n, 10]; q = c/GCD[c, n]; If[PrimeQ[q], AppendTo[lst, q]], {n, 62}]; Prepend[Sort[lst], 3] (* Arkadiusz Wesolowski, May 13 2012 *) CROSSREFS Cf. A007615 (same numbers ordered by period length). Cf. A007498, A002371, A048595, A006883, A007732, A051626, A051627. Sequence in context: A243110 A061075 A005422 * A007615 A065540 A084171 Adjacent sequences:  A040014 A040015 A040016 * A040018 A040019 A040020 KEYWORD nonn,base,nice AUTHOR STATUS approved

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Last modified October 22 19:53 EDT 2019. Contains 328319 sequences. (Running on oeis4.)