OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Perfect Power.
MATHEMATICA
{1}~Join~Map[Function[m, Function[w, 1 + Position[w, Min@ DeleteCases[w, x_ /; x < 2]][[1, 1]]]@ Table[Boole[k^# == m] # &@ IntegerExponent[m, k], {k, 2, Floor@ Sqrt@ m}]], Select[Range@ 3400, GCD @@ FactorInteger[#][[All, -1]] > 1 &]] (* Michael De Vlieger, Dec 08 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 12 2002
EXTENSIONS
Inserted a(1) = 1 by Gionata Neri, Dec 08 2016
STATUS
approved