OFFSET
1,1
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
a(n) ~ n/k, where k = 1 - 1/zeta(2) = 1 - 6/Pi^2 = A229099. - Charles R Greathouse IV, Jun 01 2018
MAPLE
filter:= proc(n) local F;
F:= map(t->t[2], ifactors(n)[2]);
max(F)>1 and igcd(op(F))=1
end proc:
select(filter, [$1..1000]); # Robert Israel, May 06 2018
MATHEMATICA
Select[Range[200], !SquareFreeQ[#] && GCD@@FactorInteger[#][[All, 2]] == 1 &]
PROG
(PARI) isok(n) = !issquarefree(n) && !ispower(n); \\ Michel Marcus, May 05 2018
(Python)
from math import isqrt
from sympy import mobius, integer_nthroot
def A303946(n):
def f(x): return int(n+sum(mobius(k)*(x//k**2) for k in range(1, isqrt(x)+1))-sum(mobius(k)*(integer_nthroot(x, k)[0]-1) for k in range(2, x.bit_length())))
m, k = n, f(n)
while m != k:
m, k = k, f(k)
return m # Chai Wah Wu, Aug 19 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 03 2018
STATUS
approved