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A340699
a(n) is the position of n^3 in the list of perfect powers.
2
1, 3, 7, 11, 15, 20, 26, 31, 36, 41, 47, 53, 61, 68, 76, 82, 89, 96, 103, 112, 121, 129, 137, 145, 153, 162, 171, 180, 189, 198, 207, 217, 226, 236, 246, 255, 265, 275, 285, 295, 306, 317, 328, 339, 350, 361, 374, 385, 396, 407, 420, 431, 443, 455, 468, 481, 494
OFFSET
1,2
LINKS
MATHEMATICA
A340699[n_] :=
First @@ Position[
Join[{1},
Select[Range[n^3], GCD @@ FactorInteger[#][[All, 2]] > 1 &]],
n^3];
Table[A340699[n], {n, 1, 57}] (* Robert P. P. McKone, Jan 17 2021 *)
PROG
(PARI) ispwr(n) = ispower(n) || (n==1); \\ A001597
Vec(select(x->ispower(x, 3), select(ispwr, [1..2*10^5]), 1)) \\ Michel Marcus, Jan 18 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Jan 17 2021
STATUS
approved