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 A172280 Primes p with the property that no divisor of p-1 is a primitive root modulo p. 1
 17, 41, 73, 89, 97, 113, 137, 193, 233, 241, 251, 257, 281, 307, 313, 337, 353, 401, 409, 433, 439, 449, 457, 499, 521, 569, 577, 593, 601, 617, 641, 643, 673, 727, 761, 769, 809, 857, 881, 919, 929, 937, 953, 977, 997, 1009, 1013, 1033, 1049, 1097, 1129, 1153 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The sequence is probably infinite. No element of A001122 nor of A172058 can be in this list. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 MATHEMATICA m = 2; t = {}; While[m < bound, m = m + 1; p = Prime[m]; dp = Divisors[p - 1]; L = Length[dp]; j = 1; While[j < L - 1, j = j + 1; b = MultiplicativeOrder[dp[[j]], p]; If[b == p - 1, j = L + 1, ] ]; If[j == L + 1, , t = {t, p}] ]; t = Flatten[t] CROSSREFS Cf. A001122 , A172058. Sequence in context: A089200 A263011 A263012 * A004625 A141174 A007519 Adjacent sequences:  A172277 A172278 A172279 * A172281 A172282 A172283 KEYWORD easy,nonn AUTHOR Emmanuel Vantieghem, Jan 30 2010 STATUS approved

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Last modified October 21 14:10 EDT 2019. Contains 328301 sequences. (Running on oeis4.)