login
This site is supported by donations to The OEIS Foundation.

 

Logo

The October issue of the Notices of the Amer. Math. Soc. has an article about the OEIS.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 A301619 A158231

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 24 20:09 EDT 2018. Contains 315356 sequences. (Running on oeis4.)