OFFSET
1,1
COMMENTS
Numbers n such that the decimal expansion of 1/n has period phi(n). For example, 1/49 has period 42.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
pr=10; Select[Range[2, 2000], MultiplicativeOrder[pr, # ] == EulerPhi[ # ] &]
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Nov 12 2009
STATUS
approved