OFFSET
1,2
LINKS
Daniel Forgues, Table of n, a(n) for n=1..10000
FORMULA
a(n) = {m}_n * (-1)^{Pi(m) - Pi(m-1)}
where {m}_n is the smallest root of {m^k}_n (the n-th perfect power with positive integer base m corresponding to largest integer exponent k) and Pi(m) is the prime counting function evaluated at m.
CROSSREFS
Cf. A157985 Perfect powers (m^k where m is an integer and k >= 2) multiplied by -1 when m is prime for largest k (m^k thus a prime power).
Cf. A157986 Largest exponents of perfect powers (m^k where m is an integer and k >= 2) multiplied by -1 when base m is prime (m^k thus a prime power).
Cf. A001597 Perfect powers: m^k where m is an integer and k >= 2.
KEYWORD
sign
AUTHOR
Daniel Forgues, Mar 10 2009, Mar 14 2009
STATUS
approved