OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Perfect Power.
MATHEMATICA
{2}~Join~Map[Function[m, Min@ DeleteCases[#, x_ /; x < 2] &@ Table[Boole[k^# == m] # &@ IntegerExponent[m, k], {k, 2, Floor@ Sqrt@ m}]], Select[Range@ 5000, GCD @@ FactorInteger[#][[All, -1]] > 1 &]] (* Michael De Vlieger, Dec 08 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 12 2002
EXTENSIONS
Definition corrected by Daniel Forgues, Mar 07 2009
Inserted a(1) = 2 by Gionata Neri, Dec 08 2016
STATUS
approved