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A060261 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. 3
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; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

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.

LINKS

Table of n, a(n) for n=0..36.

MATHEMATICA

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]]&]

CROSSREFS

The indices of these primes are in A060260. Cf. A001913, A002371, A060259, A060262.

Sequence in context: A256776 A252279 A105345 * A264348 A158231 A070815

Adjacent sequences:  A060258 A060259 A060260 * A060262 A060263 A060264

KEYWORD

nonn

AUTHOR

Jeff Burch, Mar 23 2001

EXTENSIONS

Edited by Dean Hickerson, Jun 17 2002

STATUS

approved

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Last modified January 20 02:29 EST 2018. Contains 297938 sequences.