login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A340698 a(n) is the position of n^2 in the list of perfect powers. 2
1, 2, 4, 5, 6, 9, 10, 11, 12, 13, 14, 17, 18, 19, 21, 23, 24, 25, 27, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 42, 43, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 59, 62, 63, 64, 65, 66, 67, 69, 70, 71, 73, 74, 75, 77, 78, 79, 80, 81, 82, 83, 84, 85 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

MATHEMATICA

A340698[n_] :=

  First @@ Position[

    Join[{1},

     Select[Range[n^2], GCD @@ FactorInteger[#][[All, 2]] > 1 &]],

    n^2];

Table[A340698[n], {n, 1, 67}] (* Robert P. P. McKone, Jan 17 2021 *)

PROG

(PARI) ispwr(n) = ispower(n) || (n==1); \\ A001597

Vec(select(issquare, select(ispwr, [1..5000]), 1)) \\ Michel Marcus, Jan 18 2021

CROSSREFS

Cf. A000290, A001597, A340699.

Sequence in context: A343585 A153242 A143070 * A206926 A005528 A211030

Adjacent sequences:  A340695 A340696 A340697 * A340699 A340700 A340701

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Jan 17 2021

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 18 10:47 EST 2022. Contains 350454 sequences. (Running on oeis4.)