OFFSET
1,1
COMMENTS
Conjecture: a(n) > 0 for all n.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..100000
Charles R Greathouse IV, GP script for efficiently computing the sequence
EXAMPLE
a(1) = 2 because phi(5) = 2^2. a(11) = 3 because phi(13315) = 22^3 but phi(k) is not equal to 22^2 for any k.
PROG
(PARI) a(n)=my(k=2); while(!istotient((2*n)^k), k++); k
CROSSREFS
KEYWORD
nonn
AUTHOR
Charles R Greathouse IV, Jul 14 2013
STATUS
approved