Squarefree Hilbert numbers
Problem 580
A Hilbert number is any positive integer of the form for integer . We shall define a squarefree Hilbert number as a Hilbert number which is not divisible by the square of any Hilbert number other than one. For example, is a squarefree Hilbert number, equaling . However is a Hilbert number that is not squarefree in this sense, as it is divisible by . The number is also not squarefree, as it is divisible by both and .
There are squarefree Hilbert numbers below .
How many squarefree Hilbert numbers are there below ?
How many squarefree Hilbert numbers are there below ?