OFFSET
1,2
COMMENTS
a(n) = #{A081061(k): 1<=k<=n}.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Accumulate[Table[If[PrimePowerQ[n]||Max[FactorInteger[n][[All, 1]]]<5, 1, 0], {n, 80}]] (* Harvey P. Dale, Nov 29 2020 *)
PROG
(Python)
from sympy import integer_log, primepi, integer_nthroot
def A081063(n): return int(1-(a:=n.bit_length())-(b:=integer_log(n, 3)[0])+sum((n//3**i).bit_length() for i in range(b+1))+sum(primepi(integer_nthroot(n, k)[0]) for k in range(1, a))) # Chai Wah Wu, Sep 16 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 04 2003
STATUS
approved