OFFSET
2,2
EXAMPLE
The positive integers k, k <= 6, where the positive integers <= k and coprime to k are also coprime to 6, are 1,2,6. So a(6) = the largest of these < 6, which is 2.
MATHEMATICA
f[n_] := Select[Range[n], GCD[ #, n] == 1 &]; g[n_] := Select[Range[n - 1], Times @@ GCD[f[ # ], n] == 1 &]; Max /@ Table[g[n], {n, 2, 80}] (* Ray Chandler, Dec 24 2006 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Dec 24 2006
EXTENSIONS
Extended by Ray Chandler, Dec 24 2006
STATUS
approved