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Search: id:A060262
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| A060262 |
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a(n) is the smallest x such that p(x), p(x+1), ..., p(x+n-1) all have 10 as a primitive root, but p(x-1) and p(x+n) do not, where p(n)=A000040(n) is the n-th prime. |
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+0
4
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| 4, 17, 55, 7, 93, 754, 2611, 31092, 55207, 301252, 955428, 805428
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A prime p has 10 as a primitive root iff the length of the period of the decimal expansion of 1/p is p-1.
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MATHEMATICA
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test[p_] := MultiplicativeOrder[10, p]===p-1; For[n=1, n<100, n++, a[n]=0]; v=4; While[True, For[n=1, test[Prime[v+n]], n++, Null]; If[a[n]==0, a[n]=v; Print["a(", n, ") = ", v]]; For[v+=n+1, !test[Prime[v]], v++, Null]]
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CROSSREFS
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Cf. A001913, A002371, A060259, A060260, A060261.
Sequence in context: A092091 A046995 A001585 this_sequence A108140 A121327 A027075
Adjacent sequences: A060259 A060260 A060261 this_sequence A060263 A060264 A060265
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KEYWORD
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nonn,more
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AUTHOR
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Jeff Burch (gburch(AT)erols.com), Mar 23 2001
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EXTENSIONS
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Edited by Dean Hickerson (dean(AT)math.ucdavis.edu), Jun 17 2002
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