OFFSET
5,1
REFERENCES
Tom M. Apostol, Introduction to Analytic Number Theory, Springer-Verlag, 1976, Table 10.2, pp. 216-217.
LINKS
Amiram Eldar, Table of n, a(n) for n = 5..10000
MATHEMATICA
a[n_] := Module[{p, b, lg = 1}, b = PrimitiveRoot[p = Prime[n]]; While[ PowerMod[b, lg, p] != 10, lg++]; lg]; Array[a, 100, 5] (* Jean-François Alcover, Sep 03 2016 *)
PROG
(PARI) a(n)=znlog(10, znprimroot(prime(n))) \\ Charles R Greathouse IV, Oct 03 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 09 2000
EXTENSIONS
More terms from James A. Sellers, Apr 09 2000
STATUS
approved