login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A058009 a(n) is obtained by applying the map k -> prime(k) n times, starting at n. 2
2, 5, 31, 277, 5381, 87803, 2269733, 50728129, 1559861749, 64988430769, 2428095424619, 119543903707171, 5519908106212217, 248761474969923757 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..14.

Piotr Miska, János T. Tóth, On interesting subsequences of the sequence of primes, arXiv:1908.10421 [math.NT], 2019. See DiagP.

Błażej Żmija, A note on primes with prime indices, arXiv:1909.12139 [math.NT], 2019.

EXAMPLE

a(3) is 31 because the third prime is 5, the fifth prime is 11 and for the 3rd iteration, the eleventh prime is 31.

To get a(4): 4 -> 7 -> 17 -> 59 -> 277.

MAPLE

a:= n-> (ithprime@@n)(n):

seq(a(n), n=1..8);  # Alois P. Heinz, Jun 21 2019

MATHEMATICA

Table[ Nest[ Prime, n, n ], {n, 1, 11} ]

PROG

(PARI) a(n) = my(k = n); for (j=1, n, k = prime(k); ); k; \\ Michel Marcus, Jan 01 2017

CROSSREFS

Cf. A000040, A006450, A049090, ...

For composites, see A280327. - Matthew Campbell, Jan 01 2017

Sequence in context: A119242 A068145 A032112 * A056187 A056790 A192397

Adjacent sequences:  A058006 A058007 A058008 * A058010 A058011 A058012

KEYWORD

nonn,hard,more

AUTHOR

Robert G. Wilson v, Nov 13 2000

EXTENSIONS

Edited by N. J. A. Sloane, Oct 30 2008 at the suggestion of R. J. Mathar

a(12)-a(13) from Donovan Johnson, Feb 17 2011

a(14) from Giovanni Resta, Sep 29 2019

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 July 4 18:38 EDT 2020. Contains 335448 sequences. (Running on oeis4.)