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 A242750 Positive integers n with property that n is a primitive root modulo prime(n). 7
 1, 2, 3, 6, 7, 10, 11, 13, 15, 18, 24, 26, 28, 33, 39, 41, 44, 45, 48, 50, 54, 55, 56, 58, 62, 65, 68, 69, 71, 75, 79, 83, 85, 93, 95, 107, 108, 109, 110, 117, 118, 119, 120, 123, 126, 129, 130, 131, 133, 139, 142, 143, 145, 148, 157, 158, 160, 163, 164, 166, 170, 172, 173, 174, 179, 182, 186, 190, 191, 195 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS According to the conjecture in A242748, this sequence should have infinitely many terms. LINKS Zhi-Wei Sun, Table of n, a(n) for n = 1..10000 EXAMPLE 6 is a member since 6 is a primitive root modulo prime(6) = 13, but 4 and 5 are not since 4 is not a primitive root modulo prime(4) = 7 and 5 is not a primitive root modulo prime(5) = 11. MATHEMATICA dv[n_]:=Divisors[n] n=0; Do[Do[If[Mod[k^(Part[dv[Prime[k]-1], j]), Prime[k]]==1, Goto[aa]], {j, 1, Length[dv[Prime[k]-1]]-1}]; n=n+1; Print[n, " ", k]; Label[aa]; Continue, {k, 1, 195}] CROSSREFS Cf. A000040, A000720, A242748, A242752. Sequence in context: A307414 A073439 A188084 * A299239 A107998 A276884 Adjacent sequences:  A242747 A242748 A242749 * A242751 A242752 A242753 KEYWORD nonn AUTHOR Zhi-Wei Sun, May 21 2014 STATUS approved

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Last modified July 21 05:11 EDT 2019. Contains 325189 sequences. (Running on oeis4.)