A072813 a(n)^A072814(n) is the n-th perfect power.

1, 2, 2, 3, 4, 5, 3, 2, 6, 7, 8, 9, 10, 11, 5, 2, 12, 13, 14, 6, 15, 3, 16, 17, 18, 7, 19, 20, 21, 22, 8, 23, 24, 25, 26, 27, 28, 29, 30, 31, 10, 32, 33, 34, 35, 36, 11, 37, 38, 39, 40, 41, 12, 42, 43, 44, 45, 2, 46, 3, 13, 47, 48, 49, 50, 51, 52, 14, 53, 54, 55, 5, 56, 57, 58, 15

Offset

1,2

Links

Table of n, a(n) for n=1..76.

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

Cf. A001597(n) = a(n)^A072814(n).

Sequence in context: A305815 A305789 A344568 * A285106 A369429 A120887

Adjacent sequences: A072810 A072811 A072812 * A072814 A072815 A072816

Keyword

nonn

Author

Reinhard Zumkeller, Jul 12 2002

Extensions

Inserted a(1) = 1 by Gionata Neri, Dec 08 2016

Status

approved