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Search: id:A060261
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| A060261 |
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Denoting 5 consecutive primes by p, q, r, s and t, these are the values of q such that q, r and s have 10 as a primitive root, but p and t do not. |
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+0
4
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| 257, 379, 811, 971, 1097, 1217, 2411, 2539, 2617, 3011, 4051, 5297, 5657, 6211, 6337, 6659, 6857, 8647, 8807, 10457, 10651, 10687, 10937, 11731, 11939, 12451, 12577, 13099, 14011, 14537, 14731, 14887, 15137, 15607, 15737, 16091, 16411
(list; graph; listen)
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OFFSET
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0,1
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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; Prime/@Select[Range[2, 2500], test[Prime[ # ]]&&test[Prime[ #+1]]&&test[Prime[ #+2]]&&!test[Prime[ #-1]]&&!test[Prime[ #+3]]&]
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CROSSREFS
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The indices of these primes are in A060260. Cf. A001913, A002371, A060259, A060262.
Sequence in context: A060879 A062382 A105345 this_sequence A158231 A070815 A095321
Adjacent sequences: A060258 A060259 A060260 this_sequence A060262 A060263 A060264
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KEYWORD
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nonn
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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.hickerson(AT)yahoo.com), Jun 17 2002
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