OFFSET
1,4
COMMENTS
( Sum_{d|n} (n - d) )/tau(n) is the average distance between n and its divisor.
FORMULA
MATHEMATICA
a[n_]:=Numerator[n-DivisorSigma[1, n]/DivisorSigma[0, n]]; Array[a, 70]
PROG
(Python)
from math import prod
from fractions import Fraction
from sympy import factorint
def A375080(n):
f = factorint(n).items()
return (n-Fraction(prod((p**(e+1)-1)//(p-1) for p, e in f), prod(e+1 for p, e in f))).numerator # Chai Wah Wu, Jul 30 2024
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Stefano Spezia, Jul 29 2024
STATUS
approved