login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A167797 Numbers with primitive root 10. 21

%I #7 Mar 31 2014 03:16:50

%S 7,17,19,23,29,47,49,59,61,97,109,113,131,149,167,179,181,193,223,229,

%T 233,257,263,269,289,313,337,343,361,367,379,383,389,419,433,461,487,

%U 491,499,503,509,529,541,571,577,593,619,647,659,701,709,727,743,811

%N Numbers with primitive root 10.

%C Numbers n such that the decimal expansion of 1/n has period phi(n). For example, 1/49 has period 42.

%H Vincenzo Librandi, <a href="/A167797/b167797.txt">Table of n, a(n) for n = 1..1000</a>

%t pr=10; Select[Range[2,2000], MultiplicativeOrder[pr,# ] == EulerPhi[ # ] &]

%Y Cf. A001913 (primes with primitive root 10)

%K nonn

%O 1,1

%A _T. D. Noe_, Nov 12 2009

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 11:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)