The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A289023 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A289023

Position in the sequence of numbers that are not perfect powers (A007916) of the smallest positive integer x such that for some positive integer y we have n = x^y (A052410).
(history; published version)

#18 by Susanna Cuyler at Fri May 04 22:42:51 EDT 2018

STATUS

proposed

approved

#17 by Michel Marcus at Fri May 04 01:22:26 EDT 2018

STATUS

editing

proposed

#16 by Michel Marcus at Fri May 04 01:22:23 EDT 2018

EXAMPLE

a(27)=2 because the smallest root of 27 is 3, and 3 is the second entry of A007916. a(25)=3 because the smallest root of 25 is 5, and 5 is the third 2nd entry of A007916.

a(25)=3 because the smallest root of 25 is 5, and 5 is the 3rd entry of A007916.

STATUS

proposed

editing

#15 by Jon E. Schoenfield at Thu May 03 22:01:29 EDT 2018

STATUS

editing

proposed

#14 by Jon E. Schoenfield at Thu May 03 22:01:24 EDT 2018

NAME

Position in the sequence of rootless numbers that are not perfect powers (A007916) of the smallest positive integer x such that for some positive integer y we have n = x^y (A052410).

STATUS

approved

editing

#13 by N. J. A. Sloane at Fri Aug 04 15:49:00 EDT 2017

STATUS

proposed

approved

#12 by Gus Wiseman at Wed Jul 26 11:06:24 EDT 2017

STATUS

editing

proposed

#11 by Gus Wiseman at Wed Jul 26 11:05:52 EDT 2017

EXAMPLE

a(27)=2 because the smallest root of 27 is 3, and 3 is the second entry of A007916. a(25)=3 because the smallest root of 25 is 5, and 5 is the third entry of A007916.

STATUS

proposed

editing

#10 by Michel Marcus at Wed Jul 19 07:56:37 EDT 2017

STATUS

editing

proposed

Discussion

Wed Jul 26

10:21

N. J. A. Sloane: Yes, please give an example

#9 by Michel Marcus at Wed Jul 19 07:56:03 EDT 2017

PROG

(PARI) a(n) = if (ispower(n, , &r), x = r, x = n); sum(k=2, x, ispower(k)==0); \\ Michel Marcus, Jul 19 2017

STATUS

proposed

editing