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!)
A302491 Prime numbers of squarefree index. 14
2, 3, 5, 11, 13, 17, 29, 31, 41, 43, 47, 59, 67, 73, 79, 83, 101, 109, 113, 127, 137, 139, 149, 157, 163, 167, 179, 181, 191, 199, 211, 233, 241, 257, 269, 271, 277, 283, 293, 313, 317, 331, 347, 349, 353, 367, 373, 389, 397, 401, 421, 431, 439, 443, 449, 461 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A prime index of n is a number m such that prime(m) divides n.
LINKS
FORMULA
a(n) = A000040(A005117(n)).
a(n) ~ kn log n, where k = Pi^2/6. - Charles R Greathouse IV, Aug 03 2023
MAPLE
map(ithprime, select(numtheory:-issqrfree, [$1..500])); # Robert Israel, Nov 06 2023
MATHEMATICA
Prime/@Select[Range[100], SquareFreeQ]
PROG
(PARI) forprime(p=1, 500, if(issquarefree(primepi(p)), print1(p, ", "))) \\ Felix Fröhlich, Apr 10 2018
(PARI) list(lim)=my(v=List(), k); forprime(p=2, lim\1, if(issquarefree(k++), listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Aug 03 2023
CROSSREFS
Sequence in context: A127051 A127045 A328514 * A141830 A127048 A215370
KEYWORD
nonn,easy
AUTHOR
Gus Wiseman, Apr 08 2018
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)