

A165801


f(n), f(f(n)), ... are all prime, where f(n) = (n1)/2. Stop when f(...f(n)...) is less than 4.


3




OFFSET

1,2


COMMENTS

There are no more terms since 95 is composite.


LINKS

Table of n, a(n) for n=1..10.


EXAMPLE

(951)/2=47(prime); (471)/2=23(prime); (231)/2=11(prime); (111)/2=5(prime); (51)/2=2(prime); no composite numbers smaller than 2 exist, end. (471)/2=23(prime);(231)/2=11(prime); (111)/2=5(prime); (51)/2=2; no composite numbers smaller than 2 exist, end.


MATHEMATICA

f[n_]:=Module[{k=n}, While[k>3, k=(k1)/2; If[ !PrimeQ[k], Break[]]]; PrimeQ[k]]; lst={}; Do[If[f[n], AppendTo[lst, n]], {n, 5!}]; lst


CROSSREFS

Sequence in context: A326591 A177485 A218023 * A239054 A241725 A022480
Adjacent sequences: A165798 A165799 A165800 * A165802 A165803 A165804


KEYWORD

nonn,easy,fini,full


AUTHOR

Vladimir Joseph Stephan Orlovsky, Sep 28 2009


EXTENSIONS

Corrected and edited by Charles R Greathouse IV, Oct 05 2009


STATUS

approved



