OFFSET
2,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 2..1000
FORMULA
PROG
(Python)
from math import prod
from sympy import isprime, divisors, divisor_count, prime
def A143525(n):
def mult_factors(n):
if isprime(n):
return [(n, )]
c = []
for d in divisors(n, generator=True):
if 1<d<n:
for a in mult_factors(n//d):
c.append(tuple(sorted((d, )+a)))
return list(set(c))
return int(divisor_count(min((prod(prime(i)**(j-1) for i, j in enumerate(reversed(d), 1)) for d in mult_factors(n)), default=1)-1)) # Chai Wah Wu, Aug 17 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Aug 22 2008
EXTENSIONS
Extended by Ray Chandler, Oct 11 2008
STATUS
approved