OFFSET
1,4
LINKS
MATHEMATICA
f[n_] := MultiplicativeOrder[7, n/(7^IntegerExponent[n, 7])]; Array[f, 80] (* Robert G. Wilson v, Jun 10 2011 *)
PROG
(PARI) a(n)=znorder(Mod(7, n/7^valuation(n, 7))) \\ Charles R Greathouse IV, Jun 10 2011
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Hal Sampson (hals(AT)easynet.com)
STATUS
approved