[seqfan] Re: Integers with a peculiar divisibility property

[Konstantinos Vlachopoulos]

Here is some fairly fast Python code. It uses sympy (an external library):

from sympy import divisors


def sigma(n):
    return sum(divisors(n))


def calc(n):
    return sigma(sigma(n**4)) % n**2


def test(upper, lower=1):
    for n in range(lower, upper):
        if calc(n) == 0:
            print(n)