

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
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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



